Section 2 Flashcards
1
Q
What is the reference range for total bilirubin?
A
0.2-1 mg/dL
2
Q
What is the reference range for BUN?
A
6-20 mg/dL
3
Q
What is the reference range of total calcium?
A
8.6-10 mg/dL
4
Q
What is the reference range of chloride?
A
98-107 mEq/L
5
Q
What is the reference range of creatinine
A
0.6-1.2 mg/dL
6
Q
What is the reference range for fasting glucose?
A
70-99 mg/dL
7
Q
What is the reference range for potassium?
A
3.5-5.1 mEq/L
8
Q
What is the reference range for sodium?
A
135-145 mEq/L
9
Q
What is the reference range of total protein?
A
6.4-8.3 g/dL
10
Q
What is the reference range for uric acid?
A
Male = 3.5-7.2 mg/dL
Female = 2.6-6 mg/dL
11
Q
How does diurnal variation affect chemistry values?
A
- increase in a.m. = Adrenocorticotropic hormone (ACTH), cortisol and iron
- increase in p.m. = growth hormone, parathyroid hormone (PTH), thyroid-stimulating hormone (TSH)
12
Q
What are the day to day variations that may affect chemistry values?
A
- greater than or equal to 20% for ALT, bilirubin, CK, steroid hormones, triglycerides
13
Q
What chemistry values may be affected by recent food ingestion?
A
- increased glucose, insulin, gastrin, triglycerides, sodium uric acid, LD, calcium
- decreased in chloride, phosphate, and potassium
- fasting required = fasting glucose, triglycerides, lipid panel
14
Q
What affects does alcohol have on chemistry values?
A
- decrease glucose
- increased triglycerides, and GGT
15
Q
How may posture affect chemistry values?
A
- increased albumin, cholesterol, calcium when standing
16
Q
What affects does “activity” have on chemistry values?
A
- increased in ambulatory patients: CK
- increased with exercise: potassium, lactic acid, creatinine, protein, CK, AST, LD
17
Q
How does stress affect chemistry values?
A
- increased ACTH, cortisol, and catecholamines
18
Q
How does using an isopropyl alcohol wipes to disinfect venipuncture site affect chemistry results?
A
- can compromise blood alcohol determination
19
Q
How does squeezing site of capillary puncture affect chemistry results?
A
Increased potassium
20
Q
How does pumping first during venipuncture affect chemistry results?
A
- increase potassium, lactic acid, calcium, phosphorus
- decreased pH
21
Q
How does keeping the tourniquet on longer than 1 minute affect the chemistry results?
A
- increased potassium, total protein, lactic acid
22
Q
How does IV fluid contamination affect chemistry results?
A
- increase glucose, potassium, sodium, chloride,
- possible dilution of other
23
Q
How does incorrect anticoagulant or contamination from incorrect order of draw affect the chemistry results?
A
- K2EDTA = decrease calcium and magnesium, increased potassium
- sodium heparin = increased sodium if tube is not completely full
- lithium heparin = increased lithium
- gels = some interfere with trace metals and certain drugs
24
Q
How does hemolysis affect chemistry results?
A
- increased potassium, magnesium, phosphorus, LD, AST, iron, ammonia
25
How does exposure to light affect chemistry results?
- decreased bilirubin
26
How does temperature between collection and testing?
- chilling required for lactic acid, ammonia, blood gases
27
How can inadequate centrifugation affect chemistry results?
- poor barrier formation in gel tubes can result in increased potassium, LD, AST, iron, phosphorus
28
How does delay in a separating serum/plasma (unless gel) affect chemistry results?
- increased ammonia, lactic acid, potassium, magnesium, LD
- decreased glucose (unless collected in fluoride)
29
How does recentrifugation of primary tubes affect chemistry results?
- hemolysis
- increase potassium
30
How can storage temp affect chemistry results?
- decreased at room temp = glucose
- increased at room temp = lactic acid, ammonia
- decreased at 4C = LD
- increased at 4C = ALP
31
What are higher in plasma than serum?
- total protein
- LD
- calcium
32
What are higher in serum than plasma?
- potassium
- phosphate
- glucose
- CK
- bicarbonate
- ALP
- albumin
- AST
- triglycerides
33
What is higher in plasma than whole blood?
Glucose
34
What are higher in capillary blood then venous blood?
- glucose and potassium
35
What are higher in venous blood than capillary blood?
- calcium
- total protein
36
What are higher in RBCs than plasma?
- potassium
- phosphate
- magnesium
37
What are higher in plasma than RBCs?
- sodium
- chloride
38
What is spectrophotometry?
- chemical reaction produces colored substance that absorbs light of a specific wavelength
- amount of light absorbed is directly proportional to concentration of analyte
- one of the most used methods
- used for routine chemistry assays
39
What is atomic absorption spectrophotometry?
- measures light absorbed by ground-state atoms
- hollow cathode lamp with cathode made of analyte produces wavelength specific for analyte
- sensitive
- used to measure trace metals
40
What is fluorometry?
- atoms absorb light of specific wavelength and emit light of longer wavelengths (lower energy)
- detector at 90 degrees to light source so that only light emitted by sample is measured
- more sensitivity than colorimetry
- used to measure drugs and hormones
41
What is chemiluminescence?
- chemical reaction that produces light
- usually involves oxidation of luminal, acridinium, esters, and dioxetanes
- does not require excitation radiation or monochromator like fluorometry
- extremely sensitive
- used for immunoassays
42
What is Turbidity?
- measures reduction in light transmission by particles in suspension
- used to measure proteins in urine and CSF
43
What is nephelometry?
- similar to turbidity, but light is measured at angle from light source
- used to measure antigen-antibody reaction
44
What is the wavelength when the purple is absorbed?
- 350-430 nm
- yellow is transmitted
45
What is the wavelength when blue is absorbed?
- 430-475
- orange is transmitted
46
What is the wavelength when blue-green color is absorbed?
- 475-495
- red-orange is transmitted
47
What is the wavelength when green- blue color is absorbed?
- 495-505
- orange-red is transmitted
48
What is the wavelength when green color is absorbed?
- 505-555
- red is transmitted
49
What is the wavelength when yellow-green is absorber?
- 555-575
- violet-red is transmitted
50
What is the wavelength when yellow color is absorbed?
- 575-600
- violet is transmitted
51
What is the wavelength when orange is absorbed?
- 600-650
- blue is transmitted
52
What is the wavelength when red is absorbed?
- 670-700
- green is transmitted
53
What is thin-layer chromatography (TLC)?
- used for screening tests for drugs of abuse in urine
- substances identified by retention factor (Rf) value (distance traveled by compound/distance traveled by solvent)
54
What is high performance liquid chromatography (HPLC)?
- separation of thermoliable compounds
- concentration determined by peak height ratio
- mass spectrometry can be used as detector for definitive ID
55
What is gas chromatography (GC)?
- separation of volatile compounds or compounds that can be made volatile (therapeutic and toxic drugs)
- compounds identified by retention time
- Area of peak is proportional to concentration
- mass spectrometry can be used as detector for definitive ID
56
What is ion-selective electrodes
- potential difference between 2 electrodes directly related to concentration of analyte
- used for = pH, PCO2, PO2, Na+, K+, Ca+, Li+, Cl-
57
What is osmometry?
- determines osmolality based on freezing point depression
- don’t measure volatile solute
- used for serum and urine osmolality
58
What is osmolality?
- measurement of # of dissolved particles in solution, irrespective of molecular weight, size, density, or type
59
What is electrophoresis?
- separation of charged particles in electrical field
- anions move to positivity charged pole (anode)
- cations to negatively charged pole (cathode)
- the greater the charge, the faster the migration
- used for serum protein electrophoresis, hemoglobin electrophoresis
60
What is mass spectrometry?
- generates mulitple ions from the sample than separates them according to their masss to charge ratio
- extremely sensitive and specific
- used for drugs of abuse, newborn screening, hormones, vitamins and steroid analysis
61
What tests are included in the basic metabolic panel?
- Na+
- K+
- Cl-
- CO2
- glucose
- creatinine
- BUN
- Ca+
62
What tests are included in a comprehensive metabolic panel?
- Na+
- K+
- Cl-
- CO2
- glucose
- creatinine
- BUN
- albumin
- total protein
- ALP
- AST
- bilirubin
- Ca+
63
What tests are included in an electrolyte panel?
- Na+
- K+
- Cl-
- CO2
64
What tests are include in the hepatic function panel?
- albumin
- ALT
- AST
- ALP
- bilirubin (total and direct)
- total protein
65
What tests are included in the lipid panel?
- total cholesterol
- HDL
- LDL
- triglycerides
66
What tests are included in the renal function panel?
- Na+
- K+
- CO2
- glucose
- creatinine
- BUN
- Ca+
- albumin
- phosphate
67
Describe fasting glucose
- normal = <100 mg/dL
- hyperglycemia = dibetes mellitus, other endocrine disorders, acute stress, and pancreatitis
- hypoglycemia = insulinoma, insulin-induced hypoglycemia, hypopituitarism
- major source of cellular energy
- levels decrease at RT
- used sodium fluoride to prevent glycolysis
- glucose oxidase and hexokinase are most common methods
- hexokinase is more accurate, less interfering substances
68
Describe total cholesterol
- desirable = <150 mg/dL
- limited value for predicting risk of coronary artery disease (CAD) by itself.
- used in conjunction with HDL and LDL cholesterol
- enzymatic methods most common
69
Describe HDL cholesterol
- Desirable = greater than or equal to 60 mg/dL
- appears to be inversely related to CAD
- homogenous assay don’t require pretreatment to remove non-HDL
- 1st reagent blocks non-HDL, 2nd reacts with HDL
70
Describe LDL cholesterol
- optimal = <100 mg/dL
- risk factor for CAD
- may be calculated from Friedewald formula or measured by direct homogenous assays
71
Describe triglycerides
- Desirable = <150 mg/dL
- risk factor for CAD
- main form of lipid storage
- enzymatic methods using lipase
- requires fasting specimen
72
Describe total protein
- reference range = 6.4-8.3 g/dL
- increased = dehydration, chronic inflammation, mulitple myeloma
- decreased = nephrotic syndrome, malabsorption, overhydration, hepatic insufficiency, malnutrition, agammaglobulinemia
- <4.5 g/dL associated with peripheral edema
- biuret method
- alkaline cooper reagent reacts with peptide bonds
73
Describe albumin
- reference range = 3.5-5 g/dL
- increased = dehydration
- decreased = malnutrition, liver disease, nephrotic syndrome, chronic inflammation
- largest fraction of plasma proteins
- synthesized by liver
- regulates osmotic
- measure by dye binding
74
Describe microalbumin
- performed on urine sample
- increased = diabetics at risk of nephropathy
- detects albumin in urine earlier than dipstick protein
- strict control of glucose and blood pressure can prevent progression to end-stage renal disease
- immunoassays on 24 hour urine
- alternative is albumin to creatinine ratio on random sample
75
What hormones assist in regulation of glucose?
- insulin
- glucagon
- cortisol
- epinephrine
- growth hormone
- thyroxine
76
Describe insulin
- decreases glucose levels
- responsible for entry of glucose into cells
- increases glycogenesis
- primary importance
77
Describe glucagon
- increases glucose levels
- stimulates glycogenolysis and gluconeogenesis
- inhibits glycolysis
- primary importance
78
Describe cortisol
- insulin antagonist
- increases gluconeogenesis
- secondary importance
79
Describe epinephrine
- promotes glycogenolysis and gluconeogenesis
- secondary importance
80
Describe growth hormone
- insulin antagonist
- secondary importance
81
Describe thyroxine
- increases glucose absorption from GI tract
- stimulates glycogenolysis
- negligible importance
82
Describe type 1 diabetes
- insulin-dependent diabetes mellitus
- caused by autoimmune destruction of beta cells
- absolute insulin deficiency
- genetic predisposition
- acute onset
- most develop before age 25
- dependency on injected insulin
- prone to ketoacidosis and diabetic complications
83
Describe type 2 diabetes
- non-insulin-dependent diabetes mellitus
- insulin resistance in peripheral tissue
- insulin secretory defect of beta cells
- associated with obesity
- most common type of
- not usually dependent on exogenous insulin
- not prone to ketoacidosis but common to see diabetic complications
84
Describe Gestational diabetes mellitus (GDM)
- placental lactogen inhibits action of insulin
- usually diagnosed using latter half of pregnancy
- many patients develop type 2 diabetes years later
- risk of intrauterine death or neonatal complications
-
85
Describe Pre-diabetes
- patients are unable to utilize glucose efficiently but are not yet considered fully diabetic
- at risk for diabetic complications and conversion to full diabetes (same risks as people with type 2)
86
Describe the random plasma glucose test
- diabete mellitus = greater than or equal to 200 mg/dL
- collected any time of dat without regard to time since last meal
- only for use in patients with symptoms of hyperglycemia
87
Describe fasting plasma glucose test
- pre diabetic = 100-125 mg/dL
- diabetes mellitus = greater than or equal 126 mg/dL
88
Describe oral glucose tolerance test (OGTT)
- pre-diabetic = 140-199 mg/dL. 2 hours postglucose ingestion indicates pre diabetes
- diabetes mellitus = fasting: greater than or equal to 95 mg/dL. 1 hour is greater than or equal to 180 mg/dL. 2 hour is greater than or equal to 155 mg/dL
- most often for diagnosis of gestational diabetes mellitus
- performed at 24-48 week of pregnancy
89
Describe Hemoglobin A1C test
- Pre-diabetes = 5.7-6.4%
- diabetes mellitus = greater than to or equal to 6.5%
- gives estimate of glucose control over previous 2-3 months
- should not be used for diagnosis in patients with hemoglobinopathies or abnormal RBC turnover.
- Should be performed using method certified by National Glycohemoglobin Standardization Program.
- POC assay not accurate enough
90
What is increased in uncontrolled diabetes mellitus?
- blood glucose
- urine glucose
- urine specific gravity
- glycohemoglobin
- Ketones
- anion gap
- BUN
- osmolality (serum and urine)
- cholesterol
- triglycerides
91
What is decreased in uncontrolled diabetes mellitus?
- bicarbonate
- blood pH
92
What is metabolic syndrome?
- group of risk factors that seem to promote development of artherosclerotic cardiovascular disease and type 2 diabetes mellitus
- risk factors
— decreased HDL-C
— increased LDL-C, triglycerides, BP, and blood glucose
93
Describe Phenylketonuria
- deficiency of enzyme that converts phenylalanine to tyrosine
- phenylpyruvic acid in blood and urine
- effect = intellectual disability. Urine has “mousy” odor
- diagnosis = Guthrie bacterial inhibition assay, HPLC, tandem mass spectrometry, fluorometry bans enzymatic methods. All newborns are screened
94
What is tyrosinemia?
- disorder of tyrosine catabolism.
- tyrosine and its metabolites are excreted in urine
- effect = liver and kidney disease, death
- diagnosis = MS/MS
95
What is alkaptonuria?
- deficiency of enzyme needed in metabolism of tyrosine and phenylalanine. Buildup of homogentistic acid
- effect = diapers stain black due to homogentisic acid in urine. Later in life, darkening of tissues, hips and back pain
- diagnosis = gas chromatography and MS
96
What is Maple Syrup Urine Disease (MSUD)?
- enzyme deficiency leading to buildup of leucine, isoleucine, valine
- effect = burnt sugar odor to urine, breath, skin. Failure to thrive, mental retardation, acidosis, seizures, coma and death
- diagnosis = modified Guthrie test, MS/MS
97
What is homocystinuria?
- deficiency in enzyme needed for metabolism of methionine and homocysteine build up in plasma and urine
- effect = osteoporosis, dislocated lenses in eye, mental retardation, thromboembolic events
- diagnosis = Guthrie test, MS/MS, LC-MS/MS
98
What is cystinuria?
- increased excretion of cystine due to defect in renal reabosption
- effect = Recurring kidney stones
- Diagnosis = test urine with cyanide nitro-Prusside. Positive is red-purple color
99
Describe protein electrophoresis
- Rate of migration = depends onn size, shape and charge or molecule
- support medium = cellulose acetate or agarose
- buffer = Barbital buffer, pH 8.6
- charge = at 8.6 pH, proteins are negatively charged and move toward anode
100
What is the order of migration in protein electrophoresis?
- fastest to slowest = Albumin, alpha-1, alpha-2, beta-1, beta-2, gamma
- largest = Albumin
101
What needs to be done to urine and CSF specimens before performing protein electrophoresis?
- urine = must be concentrated first because of low protein concentration. Bence Jones proteins migrate to gamma region in urine electrophoresis
- CSF = must be concentrated first because of low protein concentration. CSF has a pre
- CSF has a pre-albumin band
102
What is the protein electrophoresis pattern of acute inflammation?
- decreased albumin
- increased alpha-1 and alpha-2
103
What is the protein electrophoresis pattern for chronic infection?
- increase alpha-1, alpha-2, and gamma
104
What is the protein electrophoresis pattern for cirrhosis?
- polyclonal increased in gamma with beta-gamma bridging
105
What is the protein electrophoresis pattern of monoclonal gammopathy?
- sharp increase in 1 immunoglobulin (M Spike)
- decrease in other fractions
106
What is the protein electrophoresis pattern for polyclonal gammopathy?
- diffuse increase in gamma
107
What is the protein electrophoresis pattern for hypogammaglobulinemia?
- decreased gamma
108
What is the protein electrophoresis pattern of nephrotic syndrome?
- decreased albumin
- increased alpha-2
109
What is the protein electrophoresis pattern for alpha-1-antitrypsin deficiency?
Decreased alpha-1
110
What is the protein electrophoresis pattern of a hemolyzed specimen?
- increaesed beta or unsual band between alpha-2 and beta-1
111
What is the protein electrophoresis pattern for plasma?
- extra band (fibrinogen) between beta and gamma
112
Describe BUN and its clinical significance
- increased = kidney disease
- decreased = overhydration or liver disease
- synthesized by liver from ammonia
- excreted by kidneys
- urease reagent
113
Describe creatinine and its clinical significance
- increased = kidney disease
- waste products from dehydration of creatine (mainly in muscles)
- enzyme methods are more specific than Jaffe reaction
114
Describe Uric acid and its clinical significance
- increased = gout, renal failure, ketoacidosis, lactase excess, high nucleoprotein diet, leukemia, lymphoma, polycythemia
- decreased = administration of ACTH, renal tubular defects
- when elevated, increases risk of of renal calculi
- analyzed with urease method
- EDTA and fluoride interfere
- adjust urine pH to 7.5-8 to prevent precipitation
115
Describe ammonia and its clinical significance (plus reference range)?
- 19-60 mcg/dL
- increased = liver disease, hepatic coma, renal failure, and Reye syndrome
- high levels are neurotoxic
- collect in EDTA or heparin
- Serum may cause increase levels as NH3 is generated during clotting
- chill immediately
- Analyze ASAP
- avoid contamination from ammonia in detergents or water
116
Describe sodium and its clinical significance
- increaesed (Hypernatremia) = due to increased intake or IV, hyperaldosteronism, excess sweating, burns, diabetes insipidus
— causes tremors, irritability, confusion and coma
- decreased (hyponatremia) = due to renal or extra renal loss (vomitting, diarrhea, sweating, burns) or increased extracellular fluid volume
— causes weakness, nausea, altered mental status
- major extracellular cation
- contributes almost half to plasma osmolality
- maintains normal distribution of water and osmotic pressure
- most common method is ISE
117
Describe potassium and its clinical significance
- increased (Hyperkalemia) = due to increased intake, decreased excretion, crush injuries, metabolic acidosis
— causes muscle weakness, confusion, cardiac arrhythmia, cardiac arrest
- decreased (Hypokalemia) = due to increased GI or urinary loss, use of diuretics, metabolic alkalosis.
— causes muscles weakness, paralysis, breathing problems, cardiac arrhythmia, death
- major intracellular cation
- Most common method is ISE with valinomycin membrane
118
Describe chloride and its clinical significance
- increased (hyperchloremia) = due to same conditions as increased Na+ and excess loss of HCO3-
- decreased (hypocholermia) = from prolonged vomiting, diabetic ketoacidosis, aldosterone deficiency, salt-losing renal disease, metabolic alkalosis, compensated respiratory acidosis
- major extracellular ion
- helps maintain osmolality, blood volume, electric neutrality
- passive follows Na+
- Most common method is ISE
- sweat chloride test for diagnosis of cystic fibrosis
119
Describe total CO2 and its clinical significance (plus reference range)
- 23-29 mmol/L
- increased = metabolic alkalosis compensated respiratory acidosis
- decreased = metabolic acidosis, compensated respiratory alkalosis
- >90% is bicarbonate (HCO3-); remainder is carbonic acid (H2CO3) and dissolved CO2
- bicarbonate is important in maintaining acid-base balance
- keep sample capped to prevent loss of CO2
- measured by ISE or enzymatic method
120
Describe Magnesium and its clinical significance (plus reference range)
- 1.6-2.6 mg/dL
- increased = due to renal failure, increased intake, dehydration, bone cancer, endocrine disorders
— can cause cardiac abnormalities, paralysis, respiratory arrest coma.
- decreased = due to severe illness, GI disorders, endocrine disorder, renal loss. Can lead to cardiac arrhythmias, tremors, tetany, paralysis, psychosis, coma.
—rare in nonhospitalized patients
- essential co factor for many enzymes
- 10x more concentrated in RBCs
- avoid hemolysis
- colorimetric method most common
121
Describe calcium and its clinical significance
- increased = with primary hyperparathyroidism, cancer, multiple myeloma
— can cause cardiac weakness, coma, GI symptoms, renal, calculi
- decreased = with hypoparathyroidism, malabsorption, vitamin D deficiency, renal tubular acidosis
— leads to tetany (muscle spasms), seizures, cardiac arrhythmias
- most abundant mineral in body (99% in bones)
- regulated by PTH, vitamin D, and calcitonin
- colorimetric method for total calcium
- Ionized (free) calcium is better indicator of Calcium status. measured by ISE
- affected by pH and temp.
122
Describe phosphorus, inorganic (phosphate) and its clinical significance (plus reference range)
- 2.5-4.5 mg/dL
- increased = with renal disease, hypoparathyroidism
- decreased = with hyperparathyroidism, vitamin D deficiency, renal tubular acidosis
- major intercellular anion
- mostly in bones
- component of nucleic acids and many coenzymes
- important reservoir for energy
- should be correlated with Ca+
- higher in children
- more in RBC than plasma
- avoid hemolysis
- separate promptly
123
Describe lactate (lactic acid) and its clinical significance (plus reference range)
- 4.5-19.8 mg/dL
- sign of decreased O2 to tissues
- by products of anaerobic metabolism
- best not to use tourniquet
- patient shouldn’t make fist
- put on ice
- enzymatic methods are used
124
Describe iron and its clinical significances (plus reference range)
- male = 65-175 mcg/dL
- female = 50-170 mcg/dL
- increased = iron overdose, hemochromatosis, Sideroblastic anemia, hemolytic anemia, liver disease
- decreased = IDA
- necessary for hemoglobin synthesis
- transported by transferrin
- hemolysis interferes
- early morning specimen preferred because of diurnal variation
- colorimetric methods used
125
Describe Total iron binding capacity (TIBC) and its clinical significance (plus reference range)
- 250-425 mcg/dL
- increased = IDA
- decreased = iron overdose and hemochromatosis
- iron added to saturate transferrin
- excess removed
- iron content is determined
126
Describe % saturation or transferrin saturation and its clinical significance (plus reference range)
- 20-50%
- increased = iron overdose, hemochromatosis, Sideroblastic anemia
- decreased = IDA
- calculated value
- serum iron/TIBC x 100
127
Describe transferrin and clinical significance (plus reference range)
- 200-360 mg/dL
- increased = IDA
- decreased = iron overdose, hemochromatosis, chronic infections, and malignancies
- complex of apotransferrin (protein that transports iron) and iron
- immunoassay method is used
128
Describe ferritin and its clinical significance (plus reference range)
- male = 20-250 mcg/L
- female = 10-120 mcg/L
- increased = iron overload, hemochromatosis, chronic infections, malignancies
- decreased = IDA
- storage form of iron
- rough estimate iron content
- immunoassay method is used
129
Describe how substrate concentration influence enzymatic reaction?
- first order kinetics = enzyme > substrate
— reaction rate proportional to substrate
- second order kinetics = substrate >enzyme
— reaction rate proportional to enzyme
- assays are zero-order (excess substrate)
130
Describe how enzyme concentration influences enzymatic reactions
- velocity of reaction proportional to enzyme as long as substrate > enzyme
- unit of measure is international unit (IU)
- amount of enzyme that will catalyze 1 umol of substrate per min under standardized conditions
131
Descibe how pH infleunce enzymatic reactions
- extremes of pH may denature enzymes
- most reaction occur at pH 7-8
- used buffers to maintain optimal pH
132
Describe how temperature influences enzymatic reactions
- increase of 10C double rate of reaction until around 40-50C; then denaturation of enzyme may occur
- 37C is most commonly used in U.S.
133
Describe how cofactors influence enzymatic reactions
- nonprotein molecules = that participate in reaction. Must be present in excess
- inorganic cofactors = called activators. Either required for or enhance reaction
- organic cofactors = called coenzymes, may serve as 2nd substrate in reaction
- reaction commonly used in enzyme determinations:
— NAD (reduced form of NADH). NADH has absorbance at 340 m; NAD does not
134
Describe how inhibitors influence enzymatic reactions
- interfere with reaction
135
Describe ALP and its clinical significance
- Alkaline phosphatase
- Almost all tissues
- increased = liver and bone disease
- levels higher in biliary tract obstruction than in Hepatocellular disorders (hepatitis, cirrhosis)
- increased in children, adolescents, pregnant women, and with healing bone fractures
- optimum pH = 9-10
136
Describe AST and its clinical significance
- in many tissues, highest in liver, heart, skeletal muscle
- increase with liver disease (marked increased with viral hepatitis), AMI, and muscular dystrophy
- avoid hemolysis
- P5P is added as cofactor in chemical reaction (method of Henry)
137
Describe ALT and its clinical significance
- in liver tissues and RBCs
- increased =. With liver disease
- more specfic for liver disease than AST.
- marked increase with viral hepatitis
- glutamate is common product in both AST an ALT chemical reactions
138
Describe GGT and its clinical significance
- in liver, kidney, and pancreas tissues
- increased in all hepatobiliary disorders, chronic alcoholism
- most sensitive enzyme for all types of liver disease
- highest levels with obstructive disorders
- treatment centers use to monitor abstention
139
Describe LD and its clinical significance
- in all tissues, highest in liver, heart, skeletal muscle, RBCs
- increased = acute myocardial infarction (AMI), liver disease, pernicious anemia
- catalyze lactic acid -> pyruvic acid
- avoid hemolysis
- unstable
- store at 25C
- highest levels with pernicious anemia
- some anticoagulants interfere
140
Describe CK and its clinical significance
- tissues of cardiac muscle (CK-MB isotope), skeletal muscle and brain
- increased = AMI, muscular dystrophy
- catalyze phosphocreatine + ADP -> creatine + ATP
- most sensitive enzyme for skeletal muscle disease.
- highest levels with muscular dystrophy
- inhibited by all anticoagulants except heparin
- increased = with physical activity, intramuscular (IM) injections
- CK-MB used in diagnosis of AMI
141
Describe amylase and its clinical significance
- tissues in salivary glands, pancreas
- increased = acute pancreatitis, other abdominal diseases, mumps
- breakdown triglycerides into fatty acids and glycerol
- levels usually parallel amylase, but may stay increased longer
- more specific than amylase for pancreatic disease
142
Describe G6PD and its clinical significance
- glucose-6-phosphate dehydrogenase
- in RBCs
- inherited deficiency can lead to drug-induced hemolytic anemia
- measured in hemolysate of whole blood
143
What enzymes are tested for Hepatocellular disorders?
- AST
- ALT
- LD
144
What enzymes indicate biliary tract obstruction?
- ALP
- GGT
145
What enzymes are tested for skeletal muscle disorders?
- CK
- ALT
- LD
- Aldolase
146
What enzymes are tested for bone disorders?
ALP
147
What enzymes are tested in Acute pancreatitis
- amylase
- lipase
148
What are the cardiac markers for diagnostic AMI?
- CK-MB
- myoglobin
- cardiac troponins (cTnI or cTnT)
- draw times
— admission
—6-9 hour
— 12-24 hour if previous results were not increased
149
Describe CK-MB
- evaluation after chest pain = 4-6 hours
- duration of elevation = 2-3 hours
- sensitivity/specificity = not entirely specific to AMI
- immunoassay is used
- most often only used in combo with troponins
150
Describe myoglobin as a cardiac marker
- elevation after chest pain = 1-4 hours
- duration of elevation = 18-24 hours
- sensitivity/specificity = sensitive but not specific
- not often used but may be a part of cardiac panel
151
Describe Cardiac troponins
- elevation after chest pain = 3-10 hours
- duration of elevation = 4-10 days
- sensitivity/specificity = high sensitivity and specificity
- immunoassay used
- considered definitive marker for AMI.
- most hospitals use high sensitivity (hs) cTnI or CTnT
152
Describe test for heart failure
- B-type natriuretic peptide (BNP)
- released from heart muscle of left ventricle when fluid builds from heart failure. Acts on kidneys to increase excretion of fluid.
- NT-proBNP can be used as alternative
153
What are tests run to assess risk of CAD?
- high sensitivity CRP (hs-CRP)
- total cholesterol
- HDL cholesterol
- LDL cholesterol
- triglycerides
154
Describe high-sensitivity CRP (hs-CRP)?
- used to ID individuals at risk of cardiovascular disease
- nonspecific marker of inflammation
- best single biomarker for predicting cardiovascular events
- test on 2 occasions because of individual variability
- nephelometry and immunoassays are used
155
Describe total cholesterol tests
- most used in conjunction with HDL and LDL
- desirable = <200 mg/d:
156
Describe HDL cholesterol test
- low levels are risk factor
- desirable: greater than or equal to 60 mg/dL
157
Describe low cholesterol test
- major cause of CAD
- primary target of therapy
- optimal = <100 mg/dL
158
Describe triglyceride tests
- independent risk factor for CAD
- desirable = <150 mg/dL
159
Describe lipoprotein lipase deficiency
- extremely high triglyceride levels: 5,000-10,000
- elevated plasma Chylomicrons
- extremely “milky” looking serum
- eruptive xanthomas are common manifestation of this disease
160
Describe familial combined hyperlipidemia -
- triglycerides usually between 200-400 mg/dL
- further categorized by which lipid is elevated
161
Describe familial hypertriglyceridemia
- moderate increase in plasma triglycerides
- increased very low-density lipoprotein (VLDL), sometimes decreased HDL
- milky serum after overnight refrigeration
162
Describe familial hypercholesterolemia
- moderate increase in plasma LDL values (300-450 mg/dL)
- defect in the LDL receptor pathway leads to deposit of LDL in skin, tendons, and arteries
163
Describe Tangier Disease (hypoalphalipoproteinemia)
- decreased or absent plasma HDL
- orange-colored tonsils often present
164
Describe total bilirubin and its clinical significance
- increased = liver disease, hemolysis, hemolytic disease of newborn
- in infants, >20 mg/dL is associated with brain damage
- sum of conjugated, unconjugated, and delta bilirubin
- avoid hemolysis
- protect sample from light
- Jendrassik-Grof method, Diazo reagent
- neonate - bilirubinometry
- measures reflected light from skin using 2 wavelengths
165
Describe conjugated bilirubin and its clinical significance (plus reference range)
- “direct bilirubin”
- <0.8 mg/dL
- increased = liver disease and ostructive jaundice
- bilirubin monoglucouronide, bilirubin diglucuronide, and delta bilirubin (bound to albumin)
- Avoid hemolysis
- protect from light
- Jendrassik-Grof method and diazo reagent
- no accelerator required
166
Descibe unconjugated bilirubin and its clinical significance (plus reference range)
- “indirect bilirubin”
- <0.2 mg/dL
- increased = prehapatic, posthepatic, and some types of hepatic jaundice
- calculated value: total bili. - direct bili.
167
What are characteristics of unconjugated bilirubin?
- bound to protein (albumin)
- nonpolar
- not soluble in water
- not present in urine
- indirect reaction with diazotized sulfanilic acid
- high affinity for brain tissue (cause kernicterus)
168
What are characteristics of conjugated bilirubin?
- does not bind to protien
- polar
- soluble in water
- present in urine
- direct reaction with diazotized sulfanilic acid
- low affinity for brain tissue
169
What are test results for prehepatic jaundice?
- increased = Total bili and urine
- Normal = direct bili.
- negative for urine bili.
170
What are test results for hepatic jaundice?
- increased = total bili.
- variable direct bili.
- variable urine bili.
- decreased = urine uronilinogen
171
What are the test results for post-hepatic jaundice
- increased = total bili. And direct bili.
- positive for urine bili.
- decreased = urine urobilinogen
172
What are the hormones released from the anterior pituitary?
- ACTH
- FSH
- GH
- LC
- PRL
- TSH
173
Describe ACTH
- regulates production of adrenocortical hormones by adrenal cortex
- regulated by corticotropin-releasing hormone (CRH) from hypothalamus
- Diurnal variations: highest levels in early a.m., lowest in late afternoon
- increased in Cushing disease
- collect on ice
- store frozen
174
Describe FSH
- follicular stimulating hormone
- regulates sperm and egg production
- regulated by gonadotropin- releasing hormone (GnRH) from hypothalamus
- sharp increase just before ovulation
175
Describe growth hormone (GH)
- regulates protien synthesis, cell growth and division
- regulated by growth hormone releasing hormone (GHRH) and somatostatin from hypothalamus
- increased in gigantism, acromegaly
- decreased in dwarfism
176
Describe Luteinizing Hormone (LH)
- regulates maturation of follicles, ovulation, production of estrogen, progesterone, testosterone
- regulated by GnRH from hypothalamus
- Sharp increase just before ovulation
- home enzyme-linked immunosorbent assay (ELISA) kits to detect ovulation
177
Describe prolactin (PRL)
- regulate lactation
- regulated by prolactin-releasing factor (PRF) and prolactin-inhibiting factor (PIF) from hypothalamus
178
Describe TSH
- thyroid-stimulating hormone
- regulates production of T3 and T4 by thyroid
- regulated by thyrotropin-releasing hormone (TRH) from hypothalamus
- increased = hyperthyroidism
- decreased = hypothyroidism
179
What hormones are released by the posterior pituitary?
- ADH
- Oxytocin
180
Describe ADH
- regulates reabsorption of water in distal renal tubules
- produced in hypothalamus
- stored in posterior pituitary
- release stimulated by increased osmolality, decreased blood volume or BP
- decrease in diabetes insipidus
181
Describe oxytocin
- regulates uterine contractions during childbirth, lactation
- produced in hypothalamus
- stored in posterior pituitary
182
What hormones are released by the thyroid?
- thyroxine (T4)
- triiodothyronine (T3)
- calcitonin
183
Describe thyroxine (T4)
- regulates metabolism, growth, and development
- principle thyroid hormone
- contains 4 atoms of I
- regulated by TSH
- Most bound to thyroxine-binding globulin (TBG)
- increased in hyperthyroidism
- decreased in hypothyroidism
184
Describe Triiodothyronine (T3)
- regulates metabolism, growth and development
- most formed from deiodination of T4 by tissues.
- contains 3 atoms of I
- 4x-5x more potent than T4
- regulated by TSH
- increased in hyperthyroidism
- decreased hypothyroidism
185
Describe calcitonin
- regulate inhibition of calcium resorption
- important in diagnosis of thyroid cancer
186
Describe the parathyroid hormone
- release by the parathyroid
- regulates of calcium and phosphate
- primary hyperparathyroidism = increase PTH and calcium and decreases phosphate
- hypoparathyroidism = decreased PTH and calcium and increased phosphate
187
What are the test results for primary hypothyroidism?
- Increased = TSH
- decreased Free T4 and Free T3
188
What are test results for secondary hypothyroidism?
- decreased TSH, Free T4, and Free T3
189
what are the test results for hyperthyroidism
- decreased TSH
- Increased free T4 and free T3
190
What are the test results for T3 thyrotoxicosis?
- decreased = TSH
- normal = free T4
- increased = free T3
191
What are the hormones released by the adrenal cortex?
- aldosterone
- cortisol
192
Describe aldosterone
- regulates reabsorption of Na+ in renal tubules
- increase causes of hypertension due to water and Na+ retention
- decrease leads to severe water and electrolyte abnormalities
193
Describe cortisol
- regulates carbohydrate, fat, and protein metabolism
- water and electrolyte balance
- suppresses inflammatory and allergic reactions
- regulated by ACTH
- diurnal variation
- highest in a.m.
- increase and loss of diurnal variation in Cushing syndrome
- decrease in Addison disease
194
What hormones are released by adrenal medulla? And describe them.
- epinephrine
- norepinephrine
- epinephrine is primary hormone of adrenal medulla
- epinephrine and norepinephrine = catecholamines
- metabolites are metanephrines and vanillylmandelic acid (VMA)
- increased with pheochromocytoma
- tests = plasma and urine catecholamines and metanephrines, urine VMA
195
What are the hormones released by the ovaries?
- estrogen
- progesterone
196
Describe estrogens
- regulate development of female reproductive organs secondary sex characteristics
- regulation of menstrual cycle
- maintenance of pregnancy
- estradiol is major estrogen produced by ovaries
- most potent estrogen
- also produced in adrenal cortex
197
Describe progesterone
- regulated preparation of uterus for ovum implantation maintenance of pregnancy
- also produced by placenta
- metabolite is pregnanediol
- useful in infertility studies and to assess placental function
198
What hormones are released by the placenta?
- estrogen
- progesterone
- hCG
- inhibin A
199
Describe estrogen released by the placenta
- no hormonal activity
- used along with AFP, hCG, and inhibin A as part of the quadruple (quad) screen to monitor fetal growth and development
200
describe human chorionic gonadotropin (hCG)
- regulates progesterone production by corpus luteum during early pregnancy
- development of fetal gonads
- used to detect pregnancy, gestational trophoblastic disease, testicular tumor and other hCG-producing tumors
201
Describe Inhibin A
- regulate hormone made by the placenta
- part of Quad Screen
202
Describe testosterone
- released by testes
- regulate development of male reproductive organs and secondary sex characteristics
- two more potent metabolites are estradiol and dihydrotestosterone (DHT)
203
What hormones are released by pancreas?
- insulin
- glucagon
204
Describe insulin
- regulates carbohydrates metabolism
- produced in beta cells of islets of Langerhans
- Causes increase movement of glucose into cells for metabolism
- decreases plasma glucose levels
- decreased in diabetes mellitus
- increased with insulinoma, hypoglycemia
205
Describe glucagon
- regulates glycogenolysis, gluconeogenesis, lipolysis
- produced in alpha cells of islets of Langerhans
- increases plasma glucose levels
- Increase with glucagonoma, diabetes mellitus, pancreatitis, trauma
206
What are the endocrine disorders?
- Addison disease
- Cushing disease
- Acromegaly
- Diabetes insipidus
- pheochromocytoma
- hyperprolactinemia
207
Describe Addison disease
- decreased = cortisol and aldosterone
- increased = ACTH
- often see decreased sodium and increased potassium
- affects adrenal cortex
- screen for primary adrenal insufficiency with morning plasma cortisol
- decreased = response to cosyntropin stimulation for confirmation
- common symptoms include low BP, and darkening of the skin
208
Describe Cushing Disease
- increased cortisol and ACTH
- affects tumor of pituitary gland
- overnight dexamethasone suppression test used to confirm
209
Describe Acromegaly
- increased growth hormone
- affects pituitary gland
- oral glucose tolerance test often used to confirm: growth hormone will remain abnormally elevated q
210
Describe diabetes insipidus
- elevated plasma sodium and osmolality, decreased urine osmolality
- affects hypothalamus or kidneys
- deficient production or action of ADH leads to polyuria and polydipsia
211
Describe pheochromocytoma
- elevated plasma and urine catecholamines, metanephrines, and urine VMA
- affects adrenal medulla
- common symptoms include unexplained high BP, headaches, and sweating
212
Describe hyperprolactinemia
- elevated plasma prolactin
- affects pituitary gland
- most common endocrine disorder
- prolactin is susceptible to the hook effect
- macroprolactin can be a source of falsely elevated results
213
What is minimum effective concentration (MEC)?
- lowest concentration of drug in blood that will produce desired effect
214
What is minimum toxic concentration (MTC)?
- lowest concentration of drug in blood that will produce adverse response
215
What is therapeutic index?
- ratio of MTC to MEC
216
What is trough?
- lowest concentration of drug measured in blood.
- reached jut before next scheduled dose.
- shouldn’t fall below MEC
217
What is a peak?
- highest concentration of drug measured in blood
- drawn immediately on achievement of steady state
- should not exceed MTC
218
What is a steady state?
- amount of drug absorbed and distributed = amount of drug metabolized and excreted
- usually reached after 5-7 half lives
219
What is a half life?
- time required for concentration of drug to be decreased by half
220
What is pharmacokinetics?
- rates of absorption, distribution, biotransformation and excretion
221
What are the most common methods for therapeutic drug monitoring?
- immunoassay
- chromatography
222
What are the therapeutic drug groups?
- analgesics
- antiepileptics
- antineoplastics
- antibiotics
- cardioactives
- psychoactive
- immunosuppressants
223
What are some types of analgesics?>
- salicylates
- acetaminophen
224
What are some types of antiepileptics?
- phenobarbital
- phenytoin
- valproic acid
- carbamazepine
- ethosuximide
- felbamate
- gabapentin
- lamotrigine
225
What are some types of antineoplastics?
- methotrexate
226
What are types of antibiotics?
- aminoglycosides (amikacin, gentamicin, kanamycin, tobramycin)
- vancomycin
227
What are some types of cardioactives?
- digoxin
- disopyramide
- procainamide
- quinidine
228
What are some types of psychoactive?
- tricyclic antidepressants
- lithium
229
What are some types of immunosuppressants?
- cyclosporine
- tacrolimus
230
What are the analytic method to detect ethanol?
- gas chromatography
- enzymatic methods
231
What are the analytic methods to detect carbon monoxide?
- differential spectrophotometry
- gas chromatography
232
What is the analytic method used to detect arsenic?
- atomic absorption
233
What is the analytic method to detect Lead?
Atomic absorption
234
What analytic method is used to detect pesticides?
- measurement of serum pseudocholinesterase
235
What analytic method is used to detect methanol?
Gas chromatography
236
What drugs of abuse can be detected in urine screen?
- amphetamines
- barbiturates
- benzodiazepines
- cannabinoids
- cocaine
- methadone
- opiates
- phencyclidine
- tricyclic antidepressants
237
Describe the alpha-Fetoprotein tumor markers
- type of cancer = liver
- clinical use = aid diagnosis, monitor therapy, detect recurrence
- produced by fetal liver
- reexpressed in certain tumors
- increase in hepatitis and pregnancy
238
Describe CA 15-3 and CA 12.29
- type of cancer = breast
- clinical use = stage disease, monitor therapy, and detect recurrence
- two different assays for same marker
- can be increased with other cancers and non cancerous conditions
239
Describe CA 19-9
- type of cancer = pancreatic
- clinical use = stage disease, monitor therapy, and detect recurrence
240
Describe CA 125
Type of cancer = ovarian
- clinical use = aid diagnosis, monitor therapy, and detect recurrence
- can be increased with other cancers and gynecologists conditions
241
Describe carcinoembyronic antigen (CEA)
- type of cancer = colorectal
- clinical use = monitor therapy, detect recurrence
- fetal antigen reexpressed in tumors
- can be increased with other cancers, non-cancerous conditions and in smokers
-
242
Describe hCG tumor marker
- type of cancer = ovarian and testicular. Also, gestational trophoblastic diseases
- clinical use = aid diagnosis, monitor therapy, detect recurrence
- increased in pregnancy
243
Describe prostate-specific antigen (PSA) tumor marker
- type of cancer = prostate
- current le most widely used tumor marker
- screening asymptomatic men is controversial
- some men with prostate cancer don’t have increased PSA
- measurement of free PSA is borderline
244
Describe thyroglobulin tumor marker
- type of cancer = thyroid
- clinical use = monitor therapy, detect recurrence
- increased in other thyroid diseases
- antithyroglobulin antibodies should be measured at same time
- can interfere with assays
245
Describe an acid
- chemical that can yield H+
- protein donor
- pH <7
246
What is a base?
- chemical that can accept H+ or yield OH-
- pH >7
247
What is a buffer?
- weak acid and its salt or conjugate base
- Minimize changes in pH
- most important 1 for maintaining blood pH is bicarbonate/carbonic acid
248
What is bicarbonate?
- HCO3-
- second largest fraction of anions
- proton acceptor or base
- equal to total CO2–1
249
What is carbonic acid?
-H2CO3
- proton donor or weak acid
- equal to PCO2 x 0.03
- regulated by lungs
250
What is total CO2?
- all forms of CO2
251
What is PCO2?
- partial pressure of CO2
- directly related to amount of dissolved CO2
252
What is acidosis?
- acidemia
- blood pH <7.38
- increased HCO3-:H2CO3 ratio
- may be due to increased in HCO3- (metabolic acidosis) or increased in H2CO3 (respiratory acidosis)
253
What is alkalosis?
- alkalemia
- blood pH >7.42
- increased HCO3-:H2CO3 ratio
- may be die to increased in HCO3- (metabolic alkalosis) or decreased in H2CO3 (respiratory alkalosis)
254
What is compensated acidosis or alkalosis?
- when compensatory mechanisms have succeeded in restoring the 20:1 ratio and pH returns to normal
- Kidneys compensate for respiratory problem; lungs compensates for metabolic problem
255
What are the test results of respiratory acidosis?
- decreased = pH
- increased = PCO2
- Normal = HCO3-
- compensation to reestablish 20:1 ratio = kidneys retain HCO3-, excrete H+
256
What are the test results for metabolic acidosis?
- decreased = pH and HCO3-
- Normal = PCO2
- compensation to reestablish 20:1 ratio = hyperventilation (blow off CO2)
257
What are the test results for respiratory alkalosis?
- Increased = pH
- Decreased = PCO2
- Normal = HCO3-
- compensation to reestablish 20:1 ratio = kidneys excrete HCO3-, retain H+
258
What are the test results for metabolic alkalosis?
- increased = pH and HCO3-
- Normal = PCO2
- compensation to reestablish 20:1 ratio = hypoventilation (retain CO2)
259
What are hypoxemia?
Low O2 content in arterial blood
260
What is hypoxia?
Lack of O2 at cellular level
261
What is partial pressure?
- barometric pressure x % gas concentration
262
What is PCO2
- partial pressure of CO2 expressed in mm of Hg.
- directly related to amount of dissolved CO2
- measure of respiratory component (inversely proportional to respiration)
263
What is PO2
- partial pressure of O2
- assesses pulmonary function
264
What is the oxygen dissociation curve?
- graph showing relationship between oxygen saturation and PO2
- provides information about hemoglobin’s affinity for O2
265
What is 2,3-DPG?
- 2,3-diphosphoglycerate
- phosphate compound in RBCs that affects O2 dissociation curve
- low levels inhibit release of O2 to tissues
266
What is oxygen saturation?
- amount of O2 that is combined with hemoglobin, expressed as % of amount that can be combined with hemoglobin.
- 1 g of hemoglobin can combine with 1.34 mL of O2
267
What is P50?
- partial pressure of O2 at which hemoglobin oxygen saturation is 50%
- low value = increased oxygen affinity (shift to left)
- high value = decreased oxygen affinity (shift to right)
268
Describe pH blood gas parameter
- measurement of = H+
- derivation = pH electrode on blood gas analyzer
- reference range of arterial blood= 7.35-7.45
269
Describe PCO2 as a blood gas parameter
- measurement = partial pressure of CO2
- derivation = PCO2 electrode on blood gas analyzer
- reference range of arterial blood = 35-45 mmHg
270
Describe PO2 as a blood gas parameters
- measurement of = partial pressure of O2
- derivation = PO2 electrode on blood gas analyzer
- reference range of arterial blood = 80-100 mmHg
271
Describe HCO3- as a blood gas parameter
- measurement of = bicarbonate
- derivation = calculated value on blood gas analyzer
- reference range of arterial blood = 22-26 mmol/L
-
272
Describe total CO2 as a blood gas parameter
- measurement of = bicarbonate + carbonic acid
- derivation = calculated value on blood gas analyzer
- reference range in arterial blood = 23-27 mmol/L
273
Describe base excess as a blood gas parameters
- metabolic component of acid-base status
- difference between titratable bicarbonate of sample and that of normal blood sample
- derivative = calculated value on blood gas analyzer
- reference range of arterial blood = - 2 to +2 mEq/L
274
Describe oxygen saturation as a blood gas parameters
- measurement of = amount of oxygenated hemoglobin
- derivation = measured by oximeter
- reference range of arterial blood = 94-100%
275
What effects does hyperventilation have on arterial blood gases?
- decreased = PCO2
- increased = pH, PO2
276
What effects does a specimen exposed to air have on arterial blood gases?
- decreased = PCO2
- increased = pH and PO2
277
What effects does a specimen at RT >30 minutes have on arterial blood gases?
- decreased = PO2 and pH
- increased = PCO2
278
Describe BUN-to-creatinine ratio
- Normal range = 10-20
- Normal ratio with renal disease
- prerenal conditions: increased ratio with increased BUN and normal creatinine
- postrenal conditions: increased ratio with increased creatinine
- ratio decreases with decrease urea production
279
Describe creatinine clearance
- normal range =
— male = 97-137 mL/min
— female = 88 - 128 mL/min
- decrease renal disease (early indicator)
280
Describe albumin/globulin (AG) ratio
- normal range = 1-2.5
- reversed A/G ratio with multiple myeloma, liver disease
281
Describe amylase:creatinine clearance ratio
- normal range = 2-5%
- increased = acute pancreatitis
- decreased = macroamylasemia
282
Describe anion gap
- 10-20 OR 7-16
- differences between unmeasured anions and unmeasured cations
- increased = renal failure, diabetic acidosis, lactic acidosis, methanol, ethanol, ethylene glycol or salicylate poisoning, and laboratory error
- useful quality control
- can not be negative number
- if all determinations are increased or decreased, possible instrument error in 1 or the determinations
283
Describe calculated osmolality
- normal range = 275-295 Osm/kg
- concentration of solute
- electrolytes contribute most
- one of colligative properties
- increased dehydration, uremia, uncontrolled diabetes, alcohol or salicylate intoxication, excessive electrolyte IVs
- decreased = excessive water intake
284
Describe osmolal gap
- normal range = 0-10 moms/kg
- similar to anion gap but based on osmotically active solute concentration rather than concentration rather than concentration of ions
- >10 indicates abnormal concentration of unmeasured substance
- used to diagnosis poisonings
285
Describe urine-to-serum osmolality
- normal range = 1-3
- decrease renal tubular deficiency and diabetes insipidus
286
What is the formula for Beers law: concentration of unknown?
(Absorbance of unknown/absorbance of standard) x concentration of standard
