Intro To Lab Med Flashcards
1
Q
What are the three main exams done on urinalysis?
A
Physical exam, chemical exam and microscopic exam
2
Q
What does red urine indicate?
A
Hematuria - kidney stones, UTI or bladder cancer
3
Q
What does dark yellow urine indicate?
A
Dehydration or certain foods (carrots)
4
Q
What does brown urine indicate?
A
Glomerulonephritis, myoglobin or bile pigments
5
Q
What does orange urine indicate?
A
Medication usage including pyridium
6
Q
What is the normal range for specific gravity of urine?
A
1.001 - 1.035
7
Q
What does an high urine specific gravity indicate?
A
volume depletion
8
Q
What does a low urine specific gravity indicate?
A
excessive fluid intake, diuretic usage, diabetes insipidus
9
Q
What is the normal range for urine pH?
A
4.6 - 8.0
10
Q
What does a high urine pH indicate?
A
vomiting, UTI, kidney disease
11
Q
What does a low urine pH indicate?
A
aspirin overdose, starvation, alcohol usage, high protein diet
12
Q
What is the normal range for urine protein?
A
not present
13
Q
What does protein in the urine indicate?
A
associated with glomerulonephritis, preeclampsia, diabetes
14
Q
What is the normal range of urine glucose?
A
not present
15
Q
What does glucose in the urine indicate?
A
blood serum levels about 150-300 will cause glucose to spill into the urine. Indicates diabetes, burns, pancreatitis, corticosteroid usage, Cushing’s syndrome
16
Q
What is the normal range of ketones in the urine?
A
not present
17
Q
What does ketones in the urine indicate?
A
associated with starvation, alcoholism and diabetic ketoacidosis
18
Q
What is the normal range for Leukocyte Esterase in the urine?
A
not present
19
Q
What does leukocyte esterase in the urine indicate?
A
It shows that there were enzymes released by WBC indicating UTI. It is not specific to UTI though.
20
Q
What is the normal range for bilirubin in the urine?
A
not present
21
Q
What does bilirubin in the urine indicate?
A
Bilirubin is a byproduct of Hemolysis. Associated with biliary obstruction and liver injury.
22
Q
What is the normal range of blood in the urine?
A
not present
23
Q
What does blood in the urine indicate?
A
Associated with kidney stones, urinary trauma, UTI, strenuous exercise, and bladder cancer.
24
Q
What is the normal range of urobilinogen in the urine?
A
not present
25
What does urobilinogen in the urine indicate?
Bilirubin may interact with bacteria in the gut to produce urobilinogen which is associated with hemolysis and hepatocellular disease.
26
What is the normal range of nitrites in the urine?
not present
27
What does nitrites in the urine indicate?
Some bacteria convert nitrates into nitrites. Nitrites in the urine suggests bacterial infection which is specific but not sensitive. Negative result does not rule out infection.
28
What is the normal range of WBC in the urine in microscopic exam?
0 - 5 per high power field
29
What is the normal range of RBC in the urine in microscopic exam?
0 - 3 per high power field
30
What does the Bence Jones protein found in the microscopic exam of urine indicate?
Multiple myeloma
31
What do crystals found in the microscopic exam of urine indicate?
Associated with kidney stones
32
What do casts in the microscopic exam of urine indicate?
Casts are formed in the distal convoluted tubules of the kidney. They are abnormal proteins formed during infection or inflammation. Red blood casts are associated with glomerulonephritis. White blood casts are associated with pyelonephritis.
33
What is BUN?
Blood, Urea & Nitrogen
34
What is the normal range for BUN for adults? What units?
5-20 mg/dL
35
Urea is produced in the liver as a product of ...?
Protein catabolism
36
Urea is filtered from the blood by the _______.
kidneys
37
BUN greater than 20 mg/dL indicates...?
- Impaired kidney function
- Increased protein catabolism
- Dehydration
38
BUN less than 5 mg/dL indicates...?
- Liver failure
- Low protein diet (malnutrition)
- Endocrine disorders (that concentrate urine)
39
What is the normal creatinine range for men?
| ...for women? ...units?
- Men 0.9-1.2 mg/dL
| - Women 0.6-1.1 mg/dL
40
Elevated BUN + elevated creatinine indicates...?
kidney disease
| ... these are both excreted by the kidneys
41
Elevated creatinine indicates...?
- Impaired renal function
| - May be a 'normal' variant in persons with large muscle mass
42
Low creatinine level indicates...?
- Low muscle mass (expect low values in bedridden patients)
| - Liver disease (creatinine is a product of catabolism in the liver)
43
Which test has the highest sensitivity and specificity for kidney disease, BUN or creatinine.
Creatinine
| Elevated levels indicate kidney disease.
44
Normal uric acid level for men?
| ... for women? ...units?
- Men 3.4-8.0 mg/dL
| - Women 2.4-6 mg/dL
45
Patients suspected of having gout would have an elevated ________ _____.
Uric acid
46
Breakdown of nucleic acids forms... ?
Uric acid
47
Hyperuricemia and can lead to...?
Gout
48
Increased levels of uric acid may be caused by...?
- Excessive breakdown of nucleic acids
- Excessive destruction of cells
- Inability to excrete (urine)
49
What does CBC stand for?
complete blood count
50
What is the principal function of circulating blood?
Transportation of ...
- RBCs carrying hemoglobin
- White blood cells for defense
- Platelets responding to injury
51
What are some indications for ordering a CBC?
- Investigate disease of blood or bone marrow
- Investigate response to inflammation or infection
- Assess symptoms of fatigue, pallor, weakness, unexplained bleeding or bruising, dizziness, fever, or weight loss
52
What are the 9 common components of a CBC?
```
White blood cell count
Red blood cell count
Hemoglobin
Hematocrit
MCH
MCHC
MCV
RDW
Platelets
```
53
What does MCHC stand for and measure?
Mean corpuscular hemoglobin concentration - the average concentration of HgB in a given volume of blood.
54
What does the RDW measure?
Red cell distribution width. Degree of anisocytosis (variation in RBC size). Helps with differentiating anemias and identifying sickle cell anemia.
55
What is the normal male RBC range?
4.75-5.49 10^6 uL
56
What is the normal female RBC range?
4.15 - 4.87 10^6 uL
57
What does MCV stand for in the CBC?
Mean cellular volume (or size/volume of the red blood cell)
58
What is the normal range of the MCV?
78-98 um^3
59
What disease process can be ascertained by the MCV?
Two types of Anemia
- MCV is increased (macrocytosis) with vitamin B12 or folic acid deficiency
- MCV is decreased (microcytosis) with iron deficiency anemia
60
What is the normal range of hemoglobin for men?
14.40 – 16.60 gm/deciliter
61
What is the normal range of hemoglobin for gals?
12.2 – 14.7 gm/deciliter
62
What is the significance of the hemoglobin value?
Serves as a vehicle for transportation of oxygen and carbon dioxide - if low, inadequate tissue perfusion
63
What is hematocrit?
- Proportion of blood that is made up of red blood cells or....
- Percentage of red blood cell/total blood volume
64
What is the normal range of hematocrit for men?
40-54%
65
What is the normal range of hematocrit for females?
37-47%
66
What are some causes of elevated hemoglobin? (5)
- Loss of plasma volume (dehydration)
- high altitude state
- smokers (with COPD)
- CHF
- Polycythema vera
67
What are some causes of low hemoglobin? (5)
- Increased destruction of red blood cells
- Decreased production of RBCs
- Blood loss
- Pregnancy
- Vitamin deficiency
68
What diseases can destroy RBCs?
sickle cell disease, thalassemia (inherited blood disorder where hemoglobin is malformed causing RBC destruction)
69
What organ would be involved with decreased production of RBCs?
kidneys due to low erythropoietin release which helps regulate RBC production in the bone marrow.
70
What is the normal range for WBCs?
4,500-11,000 x cells/mm^3
71
Why would WBCs be elevated?
Infection, inflammation or stress
72
Which WBCs are considered granulocytes?
neutrophils, eosinophils, and basophils
73
Which WBCs are considered agranulocytes?
lymphocytes and monocytes
74
What factors should be considered when determining a reference range?
Age, gender, pregnancy status, lab/technique, medication, geographic etc.
75
What is a Gaussian Distribution?
Gaussian Distribution or a bell-shaped curve, is the most common method of determining a reference range. The curve represents the central 95% of normal, healthy individuals for a given test result. This "normal distribution" or reference range, can be used as a comparison to determine if a pt's values are within normal limits (WNL).
76
Identify the purpose of a Screening Test.
Identifies asymptomatic people who may have a disease.
77
Give examples of common Screening Tests.
```
Pap smear - cervical CA
Fasting blood glucose - DM
BP screening - HTN
PSA - prostate CA
Mammography - breast CA
```
78
Identify the purpose of a Diagnostic Test.
Determines the presence or absence of a disease when the pt shows signs or sxs.
79
Compare reliability vs validity.
Reliability: Consistency or reproducibility of a test under a variety of conditions.
Validity: Accuracy or sensitivity of a test.
80
Discuss the sensitivity of a test.
Measures the validity of the test for disease orientated individuals. True Positive Rate.
Helps minimize false-negatives.
SNOUT : Sensitive test with a Negative result, rules OUT disease.
A 100% sensitive test would catch all people with the disease. Positive tests do not rule people in though because some without the disease would test positive. If it ruled negative you could trust it.
81
How is sensitivity calculated?
Sensitivity = true pos. / (true pos. + false neg)
82
Discuss the specificity of a test.
Correctly identifies healthy individuals or people without disease. True Negative Rate.
Minimizes false-positives.
SPIN = Specific test with Positive results rules IN disease.
A 100% specific test would never test positive for a healthy person. Many people with the disease would test negative though. It would miss a lot of people but if it tested positive you would be sure they have the disease.
83
How is specificity calculated?
Specificity = true neg / (true neg + false pos)
84
Name 3 thyroid tests.
TSH, Free T4, T3
85
Which test is most sensitive for thyroid disorders?
TSH
86
What condition is associated with increased T4 and T3?
Hyperthyroidism
87
What condition is associated with decreased T4 and T3?
Hypothyroidism
88
T/F: You should collect a culture specimen prior to starting antibiotics?
True
89
What is the 'Gold Standard' test for diagnosis of streptococcal pharyngitis?
Throat culture
90
When would you order a urine culture?
suspected UTI or pyelonephritis
91
What can you use a sputum culture for?
Diagnosis and treatment of pneumonia and TB. It can also monitor TB therapy.
92
What test is a marker for generalized inflammation?
Sed rate
93
What are the two pancreatic enzyme tests?
Amylase
| Lipase
94
Increased levels of Amylase and Lipase may be associated with?
(3)
Pancreatitis
Biliary obstruction
Pancreatic carcinoma
95
Amylase values and what it means when elevated.
Normal value 10-130 U/L
Enzyme found in the pancreas and salivary glands
Amylase peaks earlier and declines more rapidly with pancreas inflammation
Amylase is less specific for pancreatic inflammation
96
Lipase values and what it means when its elevated.
Normal value <52 U/L
Lipase remains elevated longer
Lipase is more specific for pancreatic inflammation
97
Electrolytes Function
Determine the overall fluid status
| Acid/base status
98
What are the Electrolytes that we test for?
```
Sodium (Na+)
Potassium (K+)
Chloride
Magnesium
Calcium
```
99
Indications for ordering electrolytes
Patients receiving intravenous fluid
Metabolic or endocrine abnormalities
Medications that interfere with electrolytes
Severe vomiting/diarrhea
100
Sodium (Normal Value, Function, Regulation)
Normal value (136-145 mmol/L)
Major extracellular cation
Involved with maintenance of blood and body fluids and conduction of impulses
Regulated by osmoreceptors in the hypothalamus
Dehydration stimulates thirst
Overhydration reduces vasopressin and increases urine output
101
Elevated Sodium causes and values
(>145 mmol/L)
Not enough water in the body (dehydration)
Vomiting and diarrhea
Endocrine (SIADH, aldosteronism, or diabetes insipidus)
102
Decreased Sodium causes and values
(<136 mmol/L)
Too much water in the body (overhydration)
Endocrine (Cushings disease)
103
Potassium (Normal Value, Function)
Normal value 3.5- 5.0 mEq/L
Major intracellular cation
Involved in conduction of impulses through membrane depolarization
104
Elevated Potassium causes
(>5.0 mEq/L)
Cell injury
Kidney failure
Endocrine disorders (Addisons)
105
Decreased Potassium causes
(<3.5 mEq/L)
Malnutrition
Vomiting and diarrhea
Diuretic medications
106
Coagulation Studies - why order them?
- Unexplained bleeding disorder or excessive bruising
- Consecutive pregnancy loss
- Patients receiving heparin or coumadin therapy
107
Prothrombin Time (PT) values
- Normal 11.5-13.5 seconds
- Measure of the ‘extrinsic’ pathway of coagulation (factors I, II, V, VII, X)
- PT test may also be called INR
108
INR values
- INR (international normalized ratio measures the control against WHO standard)
* Used to monitor patients who are on coumadin therapy, therapeutic value of 2-3.
109
Partial Thromboplastin Time (aPTT) values
- Normal 27-38 seconds
- Measures ‘intrinsic’ coagulation pathway
- Most commonly used to monitor heparin therapy
110
Reasons for Prolonged Coagulation Studies
- Patients on coumadin or heparin therapy
- Liver injury (cirrhosis)
- Vitamin K deficiency
111
What are the liver functions
conjugation of bilirubin
synthesis of proteins and clotting factors
involved in storage and disposal of nutrients, drugs and toxins
112
What are the liver profile tests (6)
```
Aspartate aminotransferase (AST)
Alanine aminotransferase (ALT)
Gamma glutamyl transpeptidase (GGT)
Alkaline phosphatase
Bilirubin
Albumin
```
113
What does the AST indicate and its values
Normal value is 7-42 IU/liter
| May be elevated with liver, muscle, or cardiac injury
114
What does the ALT indicate and its values
Normal value is 1-45 IU/liter
| More sensitive for liver injury
115
What does the Alkaline Phosphatase indicate and its values
1. Normal value 25-160 IU/L
2. Elevated with bile duct obstruction
a. Extrahepatic obstruction (cholecystitis)
b. Intrahepatic obstruction (viral hepatitis or cirrhosis)
3. This enzyme is not specific to the biliary tract and may be increased with new bone cell production
a. Metastatic bone cancer
116
What does the Gamma glutamyl transpeptidase (GGT) indicate
1. Elevated with liver injury, or biliary obstruction
2. Used as a marker of alcohol use
a. Levels may remain elevated long after abstinence from alcohol (3-6 weeks), making it useful for monitoring alcohol treatment programs
117
What does bilirubin indicate
- Breakdown product of hemoglobin
- Unconjugated bilirubin
a. Bilirubin bound by albumin (not water soluble)
b. Elevated with hemolysis
- Conjugated
a. Bilirubin cleaved of albumin (water soluble)
b. Elevated with bile duct obstruction
118
What does albumin indicate
Protein synthesized in the liver
| Marker of liver function
119
Prothrombin time
1. Measures the time required for coagulation to occur
2. Coagulation proteins are produced in the liver
3. Deficient numbers of coagulation proteins will prolong the prothrombin time
4. Marker of liver function
120
What is the normal value range for Chloride?
97 - 107 mEq/L
121
What are two causes of elevated chloride levels?
- dehydration
| - overactive parathyroid glands
122
What is a cause of decreased chloride levels?
vomiting (by loss of HCl in gastric acid)
123
What is the normal value range for Magnesium
1.3 - 2.1 mg/dl
124
What are two causes of elevated magnesium levels?
- kidney disease
| - use of antacids (Milk of Magnesia)
125
What are two causes of decreased magnesium levels?
- inadequate absorption in GI tract
| - medications, such as diuretics
126
What is the normal value range for Calcium?
8.2 - 10.2 mg/dl
127
Where is 99% of calcium stored?
in bone
128
What circulating calcium is metabolically active - 1) protein-bound (with albumin) or 2) ionized
ionized
129
What are common causes of elevated calcium levels?
- hyperparathyroid hormones
- cancer
- excessive vitamin D
130
What are common causes of decreased calcium levels?
- hypoparathyroid hormones
- deficient protein
- vitamin D deficiency
131
What is the fasting blood glucose level?
< 110
132
Elevated glucose in the blood may be a sign of ...?
- diabetes
- endocrine disorders
- pancreatitis
- prednisone therapy
133
What is the normal value for hemoglobin A1C?
< 5%
134
What does hemoglobin A1C measure?
Glycosylated hemoglobin (this reflects the average blood glucose over the past 2-3 months and is a useful measure for diabetes management)
