Clinical Chemistry Flashcards
(147 cards)
1
Q
Hemolysis
A
The destruction of erythrocytes
2
Q
Icterus
A
yellowing of the skin and the whites of the eyes caused by an accumulation of bile pigment (bilirubin) in the blood
Also called jaundice
3
Q
Lipemia
A
The presence of fatty material in plasma or serum
4
Q
Plasma
A
The fluid portion of blood
5
Q
Reference range
A
Normal values
6
Q
Serum
A
The fluid portion of blood after it has clotted
It does not contain cells or coagulation proteins
7
Q
Describe proper sample processing for plasma samples
A
- Collect a blood sample in an appropriate container
- Mix the container with a gentle rocking motion
- Make sure the container is covered to prevent evaporation during centrifugation
- Centrifuge at 2000-3000 rpm for 10 minutes
- Carefully remove the fluid plasma layer from the bottom layer of cells with a capillary pipette
- Transfer the plasma to properly labeled container
- Process the sample immediately or refrigerate or freeze as needed
8
Q
Describe proper sample processing for serum samples.
A
- Collect a whole blood sample in a container that contains no anticoagulant
- Allow the blood to clot in its original container at room temp for 20-30 mins
- Gently separate the clot from the container by running a wooden applicator stick around the wall between the clot and the wall
- Cover the sample and centrifuge it at 2000-3000 rpm for 10 minutes
- Remove the serum from the clot with a capillary pipette
- Transfer the serum to an appropriately labeled container
- Refrigerate or freeze the sample as appropriate
9
Q
Discuss the effects of sample quality in test results.
A
Lipemia: light scattering, volume displacement, or hemolysis
Hemolysis/blood substitutes: release of analytes, release of enzymes, reaction inhibition, increased optical density(absorbance), release of water
Icterus: spectral interference, chemical interaction
Hyperproteinemia: hyperviscosity, analyte binding, volume displacement
Medications: reaction interference
10
Q
List the common causes of sample compromise.
A
Lipemia
Hemolysis/blood substitutes
Icterus
Hyperproteinemia
Medications
11
Q
Describe how to minimize causes of hemolysis
A
Use a completely dry syringe
Remove the needle from the syringe before transferring the blood
Too much alcohol on the injection site
12
Q
Describe how to minimize the causes of chemical contamination.
A
Tubes need to be chemically pure, and detergents completely rinsed from reusable tubes
13
Q
Describe how to minimize the causes of improper labeling
A
ALWAYS label the tube with the date, time of collection, patient’s ID number or name
ALWAYS DOUBLE CHECK SAMPLE IDENTIFICATION
14
Q
Describe how to minimize the causes of improper sample handling.
A
All chemical measurements should be completed within 1 hour of sample collection or properly handled and stored
Samples cannot become too warm
If a sample is frozen, use gentle inversion after thawing
15
Q
Describe how to minimize the causes of patient influences
A
Try to obtain sample from fasted animal
Water restriction is not necessary
16
Q
Beer’s law
A
A principle that describes the relationship between light absorbance, transmission, and the concentration of a substance in a solution
17
Q
End point assay
A
A chemical reaction that proceeds to a stable end point
18
Q
Ion-selective electrode
A
19
Q
Kinetic assay
A
A chemical test that measures the rate of change of a substance in the test system
20
Q
Optical density
A
The degree to which light is transmitted through a medium
21
Q
Reflectometer
A
an instrument for measuring quantities associated with reflection
22
Q
Spectrophotometer
A
A piece of equipment designed to measure the amount of light that is transmitted through a solution
23
Q
Describe the principle of refractometry
A
based on a transparent or translucent material’s ability to refract and shift light, also known as its refractive index
24
Q
Describe the principle of photometry
A
to measure the intensity of light by converting light into electricity
25
Differentiate between kinetic and end point assays
End-point essays form a stable product, while kinetic assays are more volatile
Kinetic assays use enzymes as reagents or are designed to measure enzyme concentrations
Kinetic assays are evaluated by measuring the difference in color changed at specific times after the reaction begins, while end-point assays use either a one-point calibration method or a standard curb to provide results
26
List the features and benefits of dry system analyzers.
Include reagent-impregnated slides, pads, or cartridges
Most use reflectance assays
Have higher costs
Do not require reagent handling performing single tests is pretty simple
Can allow for loading large numbers of slides to minimize the time required to prepare the analyzer
27
List the features and benefits of liquid system analyzers.
Use a lyophilized reagent or an already prepared liquid reagent
Rotor-based systems tend to be quite accurate
More cost-effective but cannot run single tests
All can be integrated into a software system
28
List the features and benefits of dedicated-use system analyzers.
Available for certain tests
Utilize electrochemical technology
Can be used if only a single test is requested or emergency situations
29
Acute-phase proteins
Proteins, including serum amyloid A and C-reactive protein, that are produced by hepatocytes immediately following injury or inflammation
30
Alanine transaminase
Cytoplasmic enzyme of hepatocytes released when hepatocytes are damaged
31
Albumin
A group of plasma proteins that comprises the majority of protein in plasma
32
Alkaline phosphatase
A group of enzymes that functions at an alkaline pH and catalyzes the reactions of organic phosphates
33
Aspartate transaminase
An enzyme that is present in body serum and in certain body tissues that catalyzes the transfer of an amino group from aspartic acid to alpha-ketoglutaric acid, thereby forming glutamic acid and oxaloacetic
34
Bile acids
A group of compounds that are synthesized by hepatocytes from cholesterol that help with fat absorption
35
Bilirubin
An insoluble pigment derived from the breakdown of hemoglobin, which is processed by hepatocytes
36
Cholesterol
A plasma lipoprotein that is produced primarily in the liver as well as ingested in food
Used in the synthesis of bile acids
37
Conjugated bilirubin
Bilirubin that has been taken up by the liver cells and conjugated to form the water-soluble compound bilirubin diglucuronide
38
Gamma glutamyltransferase
An intracellular enzyme found in high concentrations in liver, pancreatic, and renal tubular cells
39
Globulins
A complex group of plasma proteins that have been designated as alpha, beta, or gamma
Include immunoglobulins, complement, and transferrin
40
Glutamate dehydrogenase
A mitochondrial-bound enzyme that is found in high concentrations in the hepatocytes of cattle, sheep, and goats
41
Hepatoencephalopathy
Severe hepatic insufficiency that may induce a syndrome of excitability, tremor, compulsive walking, head pressing, and apparemt blindness, followed by coma and convulsions
42
Hyperlipoproteinemia
A condition characterized by excess lipids in the blood
Also called hyperlipidemia and hyperlipemia
43
Hyperproteinemia
An increased protein level in the blood
44
Hypoalbuminemia
A decrease in the circulating levels of albumin in the blood
45
Hypoglycemia
A decreased plasma glucose level
46
Hypoproteinemia
A condition characterized by an abnormally low level of protein in the blood
47
Iditol dehydrogenase
An enzyme of the oxidoreductase class that catalyzes the oxidation of l-iditol to l-fructose
Occurs in significant quantities only in the liver, and its increased activity in serum is used as an indicator of parenchymal liver damage
48
Jaundice
A condition characterized by hyperbilirubinemia and the deposition of bile pigments in the skin, mucous membranes, and sclera
49
Protein
50
List the potential causes of alterations in serum proteins.
Disease conditions such as liver and kidney
Age-related changes
51
Describe the commonly performed tests to measure total protein and albumin.
Fibrinogen values
Total protein is usually measured with a Refractometer
Most common test for albumin is dye-binding assay
52
Describe the common method for determining globulin concentration.
Direct measurement of globulin isn't usually performed
Globulin concentration is calculated by subtracting the albumin concentration from the total serum protein
53
List the commonly performed tests for the evaluation of the hepatobility system.
Bile acids test
Enzymes analyses
Phosphatases
Transferases
Dehydrogenases
54
Describe the metabolism of bilirubin.
1) production
2) uptake by the hepatocyte
3) conjugation
4) excretion into bile ducts
5) delivery to the intestine
55
Differentiate between conjugated and unconjugated bilirubin.
Conjugated bilirubin is not reabsorbed from the proximal intestine as mentioned above; in comparison
unconjugated bilirubin is partially reabsorbed across the lipid membrane of the small intestinal epithelium and undergoes enterohepatic circulation
56
List the leakage enzymes.
Alanine transaminase (ALT)
Aspartate transaminase (AST)
Iditol dehydrogenase (ID)
Glutamate dehydrogenase (GLDH)
57
Explain the significance of altered enzyme activity.
Temperature
pH
Substrate concentration
58
Describe the circulation of bile acids and the significance of altered bile activity.
Bile acids are released when the gallbladder contracts in association with feeding. Most bile acids enter the intestinal tract, where they participate in fat absorption. Some bile acids are then excreted with the feces, and some are absorbed through the portal circulation.
59
Allantoin
A crystalline substance produced by the oxidation of uric acid by uricase and present in the urine of most mammals except primates and Dalmation dogs
60
Azotemia
The increased retention of urea in the blood
61
Blood urea nitrogen
The principal end product of amino acid breakdown in mammals
62
Creatinine
A waste product that is formed during normal muscle cell metabolism
63
Effective renal plasma flow
The effective rate of blood flow through the kidneys
The determining factor relative to the rate of glomerular filtration
64
Enzymuria
The presence of specific enzymes in urine
65
Fractional excretion of electrolytes
A mathematical manipulation that describes the excretion of specific electrolytes relative to the glomerular filtration rate
66
Glomerular filtration rate
The rate at which substances are filtered through the glomerulus and excreted in the urine
67
Uric acid
A metabolic by-product of nitrogen catabolism
68
Discuss the role of kidneys in maintaining homeostasis.
They maintain the volume and composition of extracellular fluid and are involved in the excretion of metabolic waste products and other chemicals
69
Describe the commonly performed tests of kidney function.
Blood urea nitrogen
Serum creatinine
BUN/Crea ratio
UP/Crea ratio
Uric acid
70
Describe the relationship between urea nitrogen and creatinine
BUN and CREA have an inverse logarithmic relationship
Can be used to track progress of disease and effectiveness of treatment
71
Discuss the tests for effective renal plasma flow and glomerular filtration rate.
Exogenous creatinine clearance
Endogenous creatinine clearance
Effective renal plasma flow (ERPF)
Glomerular filtration rate (GFR)
Iohexol clearance
Single injection inulin clearance
Fractional clearance of electrolytes
Water deprivation tests
Inorganic phosphorus (Pi)
72
Discuss the breakdown of nitrogenous products and the role of kidneys
Urea is the end product of amino acid breakdown in mammals
Kidneys remove nitrogenous waste (urea) from blood
73
Acinar
Pertaining to or affecting an acinus or acini
Refers specifically to glandular tissue with a structure that is often described as grapevine clusters
74
Amylase
An enzyme derived primarily from the pancreas that functions in the breakdown of starch
75
Amyloclastic
A method of measuring serum amylase by evaluating the disappearance of starch substrate
76
Endocrine
A term that refers to the system of glands and other structures that secrete hormones directly into the circulatory system
77
Fructosamine
A molecule formed as a result of the irreversible reaction of glucose bound to protein
78
Glucagon
A hormone secreted by the alpha cells of thenislets of Langerhans in response to hypoglycemia
79
Glucose
A monosaccharide that represents the end product of carbohydrate tolerance
80
Glucose tolerance
A metabolic test of carbohydrate tolerance
81
Glycosylated hemoglobin
The irreversible reaction of hemoglobin bound to glucose
82
Hyperglycemia
An abnormally increased glucose level in the blood
83
Insulin
A protein hormone that is secreted by the beta cells of the pancreatic islets in response to elevated blood levels of glucose and amino acids
84
Lipase
A pancreatic enzyme that functions in the breakdown of fats
85
Pancreatic lipase immunoreactivity
86
Trypsin
A proteolytic digestive enzyme that is produced by the exorcize pancreas and that catalyzes the breakdown of dietary proteins into peptones, peptides, and amino acids in the small intestine
87
Trypsinogen
The inactive precursor form of trypsin
It is secreted in pancreatic juice and converted into active trypsin through the action of enterokinase in the intestine
88
Differentiate between the acinar and endocrine functions of the pancreas.
Acinar functions: amylase and lipase
Endocrine functions: glucose, fructosamine, and glycosylated hemoglobin
89
List and describe the common tests for the evaluation of the exocrine pancreas.
Amylase
Lipase
Amylase and lipase in peritoneal fluid
Trypsin
Serum trypsinlike immunoreactivity
Serum pancreatic lipase immunoreactivity
90
Explain the relationship between insulin, glucagon, and blood glucose.
Glucagon is a hormone that your pancreas makes to help regulate your blood glucose (sugar) levels. Glucagon increases your blood sugar level and prevents it from dropping too low, whereas insulin, another hormone, decreases blood sugar levels
91
Describe the common tests that are used to evaluate patients for hyperglycemia
Fructosamine
Glycosylated Hemoglobin (Hemoglobin A1C)
B-hydroxybutyrate
Glucose tolerance
92
Discuss the general concepts involved in the performance of glucose tolerance tests
Aid in diagnosing diabetes mellitus and in determining insulin regimens for diabetic patients
All tests require the patient to be given glucose (PO or IV) and then serial determinations of blood glucose levels are determined
It challenges the pancreas with a glucose load and measures the effect by evaluation of blood or urine concentrations
Prolonged hyperglycemia or glucosuria after a glucose tolerance test indicates diabetes mellitus
93
Acid-base balance
A state of equilibrium between the acidity and alkalinity of the body fluids
Also called hydrogen ion balance
94
Acidosis
A pathologic decrease in pH of blood or body tissues as a result of the accumulation of acids or a decrease in bicarbonate
95
Alkalosis
A condition in which the blood pH is higher than 7.45
96
Anion
A negatively charged ion
97
Anion gap
Used to evaluate a patient's acid-base status
Calculation is based on subtracting the sum of measured major serum anions from the sum of measured major serum cations
98
Base excess
The amount of acid or base required to titration a sample of whole arterial blood to the normal pH of 7.4
99
Bicarbonate
An electrolyte in plasma
Part of the bicarbonate-carbonic acid buffer system that maintains the blood pH in equilibrium
100
Buffers
A substance that increases the amount of acid or alkali necessary to produce a unit change in pH
101
Calcium
The most abundant mineral in the body
Important cation in intracellular and extracellular fluid
Essential to normal clotting of blood, maintenance of normal heartbeat, and the initiation of neuromuscular and metabolic activities
102
Cation
A positively charged ion
103
Chloride
The principal anion in extracellular fluid and gastric juice
104
Electrolytes
Any substance that dissociated into ioms when in solution
105
Hypercalcemia
An increased plasma calcium level
106
Hypercapnia
Am excess of carbon dioxide in the blood that is indicated by an elevated PCO2 level as determined by blood gas analysis and that results in respiratory acidosis
107
Hyperkalemia
An increased plasma potassium level
108
Hypernatremia
An increased plasma sodium level
109
Hyperphosphatemia
An excessive amount of phosphates in the blood
110
Hypocalcemia
A decreased plasma calcium level
111
Hypocapnia
A deficiency of carbon dioxide in the blood
112
Hypokalemia
A decreased plasma potassium level
113
Hyponatremia
A decreased plasma sodium level
114
Hypophospatemia
A decreased amount of phosphates in the blood
115
Describe the blood buffer systems and their role in the maintenance of the acid-base balance
Blood buffers counteract imbalance by altering H+ concentration to regulate the pH in acid-base balance
116
Explain the effect of respiratory rate on the acid-base balance
a reduced respiratory rate will lead to a decreased pH; the more carbon dioxide is exhaled, the less carbon dioxide is present for this reaction
117
Respiratory acidosis
a condition that occurs when your lungs can't remove all of the carbon dioxide produced by your body
118
Respiratory alkalosis
a condition marked by a low level of carbon dioxide in the blood due to breathing excessively
119
Metabolic acidosis
A condition in which too much acid accumulates in the body
120
Metabolic alkalosis
a disease state where the body's pH is elevated to greater than 7.45 secondary to some metabolic process
121
List the major cations in plasma and describe their roles.
Sodium: plays a role in water distribution and body fluid osmotic pressure maintenance
Potassium: important in normal muscular function, respiration, cardiac function, nerve impulse transmission, and carbohydrate metabolism
Calcium: found in bone
Magnesium: activates enzyme systems
Hydrogen:
122
List the major anions in plasma and describe their roles
Chloride: plays a role in maintenance of water distribution, osmotic pressure, and normal anion/cation ratio
Bicarbonate: help keep a normal acid-base (pH) balance
Phosphate: energy storage, involvement in carbohydrate metabolism
123
List common conditions related to altered serum electrolyte levels
Calcium: hypercalcemia and hypocalcemia
Chloride: hyperchloremia and hypochloremia
Magnesium: hypermagnesemia and hypomagnesemia
Phosphate: hyperphosphatemia or hypophosphatemia
Potassium: hyperkalemia and hypokalemia
Sodium: hypernatremia and hyponatremia
124
Describe the anion gap evaluation and explain how it is calculated.
Any difference between the total positive charges and the total negative charges
(Na+K) - (Cl+HCO3) = Anion Gap
125
ACTH stimulation test
A test designed to test the response of the hormone that stimulates adrenocorticol growth and secretion
126
Adrenocorticotropic hormone (ACTH)
A hormone secreted by the anterior pituitary gland that has a stimulating effect in the adrenal cortex
127
Cortisol
A steroid hormone produced by the adrenal glands
128
Creatinine kinase
An enzyme that is found predominantly in cells of the heart, brain, and skeletal muscle
Released when cells are damaged
129
Dexamethasone suppression test
An endocrine system test designed to detect hyperadrenocorticism
130
Ethylene glycol
A solvent with a sweet, acrid taste that is found in many products such as antifreeze, drying agents, and inks
Ingestion or excessive skin exposure can be toxic
131
Hematochezia
The presence of blood in the feces
132
Hyperadrenocorticism (Cushing's Disease)
The abnormally increased secretion of adrenocorticol hormones
133
Hypoadrenocorticism (Addison's disease)
A deficiency in the production of mineralcorticoid or glucocorticpid steroid hormones
134
Hyperthyroidism
A condition that is caused by the excessive production of iodinated thyroid hormones
135
Lactate
The anionic form of lactic acid
A salt of lactic acid
136
Melena
dark sticky feces containing partly digested blood
137
Mucin clot test
The adding of acetic acid to normal synovial fluid, which causes clot formation
Compactness of the clot and the clarity of the supernatant fluid are the criteria on which the result is based
138
Plumbism
A chronic form of lead poisoning that is caused by the absorption of lead or lead salts
139
Thyroid-stimulating hormone
A substance secreted by the anterior lobe of the pituitary gland that controls the release of thyroid hormone and that is necessary for the growth and function of the thyroid gland
140
Thyroxine
A hormone of the thyroid gland that is derived from tyrosine and that influences the metabolic rate
141
Describe the relevance of creatine kinase testing for the diagnosis of liver or skeletal muscle damage.
Creatine kinase is produced in striated muscle cells and leaks out of damaged muscles
The test doesn't reveal which muscle is damaged
142
Describe the use of lactate evaluation for critical patients.
Presence of lactate does not indicate a specific disease but does indicate hypoxia or hypoperfusion
143
Discuss the indications for ACTH stimulation and Dex suppression tests.
ACTH: evaluates the degree of adrenal gland response to administration of exogenous ACTH
Dex suppression: confirms or replaces ACTH response test for hyperadrenocorticism
144
Discuss the production and action of thyroxine
Composed of T3 and T4
controls how much energy your body uses (the metabolic rate); it's also involved in digestion, how your heart and muscles work, brain development and bone health
145
Describe the chemical tests of gastrointestinal function.
Monosaccharide absorption tests
d-Xylose absorption
Fecal occult blood
Serum folate and cobalamin
146
Describe the handling of samples for toxicology testing.
Samples must be free of contamination by environmental compounds and debris
Make sure it is LABELED!
147
Describe common toxicology testing.
Nitrate or nitrite poisoning: diphenylamine test
Anticoagulant and reodenticides: coagulation panel
Chemicals that denatured hemoglobin: demonstration of Heinz bodies on a blood smear
Ethylene glycol: Urine sediments
