Lab Medicine Flashcards
1
Q
Roles of Laboratory Medicine
A
Diagnosis of disease
Monitoring of disease, therapies and interventions,
Screening for disease
Reserach
2
Q
Gaussian Distribution
A
95% of the normal healthy population falls within the normal test range
5% do not fall within the range when they are healthy
3
Q
Screening Test
A
Identifies asymptomatic people who MAY have a disease
4
Q
Diagnostic Test
A
Determines presence or absence of disease when a patient SHOWS SIGNS/SYMPTOMS
5
Q
Fecal occult blood test screens for
A
Colorectal cancer
6
Q
Blood pressure screens for
A
hypertension
7
Q
Bone densitometry screens for
A
osteoporosis & osteopenia
8
Q
PSA screens for
A
prostate cancer
9
Q
PPD test screens for
A
tuberculosis
10
Q
Validity
A
how well a test tells who has a disease and who doesn’t
11
Q
Reliability
A
consistency of a test at different/times conditions (getting same result)
“Consistent”
12
Q
Specificity
A
Health oriented
Identifies those WITHOUT disease correctly
Minimizes FALSE POSITIVES
“SPIN”
13
Q
Sensitivity
A
Disease-oriented
Identifies those WITH disease correctly
Minimizes FALSE NEGATIVES
“SNOUT”
14
Q
RBC Reference Range (per microliter)
A
Male: 4.73-5.49
Female: 4.15-4.87
15
Q
Mean cellular (corpuscular) volume (MCV)
A
Average volume of blood cells
Normal (76-100 micrometers^3)
Helps classify anemia type
16
Q
Increased MCV
A
(macrocytosis)
vitamin B12 or folic acid deficiency
17
Q
Decreased MCV
A
(microcytosis)
iron deficiency anemia
18
Q
Hemoglobin Reference Range
A
Male: 14.40-16.60 gm/dl
Female: 12.2-14.7 gm/dl
19
Q
Hematocrit Reference Range
A
Men: 42.9-49.1%
Women: 37.9-43.9%
Percentage of RBC making up total blood volume
20
Q
Elevated hemoglobin causes
A
Loss of plasma volume (dehydration) High altitude Smokers (w/ COPD) Congenital heart disease Polycythema vera (overproduction of RBC)
21
Q
Low hemoglobin causes
A
^ destruction of RBC Decreased RBC production Blood loss Pregnancy Vitamin deficiency (iron)
22
Q
WBC Reference Range
A
4,500-11,000 per mm^3
23
Q
WBC Granulocytes
A
Neutrophils, eosinophils, basophils
24
Q
WBC agranulocytes
A
Lymphocytes and monocytes
25
Elevated Neutrophils
(most common WBC)
Normallly 56%
BACTERIAL INFECTIONS
Inflammatory conditions
Other infections
26
Elevated Basophils
| Normally 0.5%
Elevated CML (chronic myeloid leukemia)
Aftermath of splenectomy
Polycythemia
27
Decreased basophils
rheumatic fever, pregnancy, post-radiation therapy, and steroid therapy
28
Elevated eosinophils
| Normally 2.7%
allergies, parasitic infection or skin disease
29
Elevated lymphocytes
| Normally 34%
Viral infection or lymphocytic leukemia
30
Elevated monocytes
| Normally 4%
Phagocytosis of bacterial infections
31
Elevated WBC
| "Leukocytosis"
```
Acute (viral/bacterial) infections, leukemia, post-splenectomy, steroids (prednisone)
WITHOUT DISEASE (high stress, excitement, pain, trauma, heat)
```
32
Low WBC
| "Leukopenia"
Viral infection; overwhelming bacterial infection, hypersplenism (enlarged spleen); meds/toxins suppressing bone marrow
33
Platelet Reference Range
150,000 - 400,000 per cubic mililiter
34
Low Platelets
Enlarged spleen, platelet destruction (DIC, ITP), decreased platelet production (bone marrow suppression, viral infection, vit. deficiency), alcoholism
35
Elevated platelets
Hemorrhage
Splenectomy
Inflammation
36
Urinalysis identifies:
stones, UTI and urologic malignancy, systemic disease
SAMPLE CAUGHT MID-STREAM; examined within 1-2 hrs
37
Urinalysis Physical Exam
Color, clarity, odor
38
Urinalysis Chemical Exam
Dipstick
39
Urinalysis Microscopic Exam
Looks for RBC, WBC, casts or crystals
40
Red urine (hematuria)
Kidney stones, UTI or bladder cancer
41
Yellow urine
Dehydration or foods (carrots)
42
Brown urine
Glomerulonephritis, myoglobin, or bile pigments (kidney/liver functions)
43
Orange
medication side affects
44
Urinalysis (Chemical Exam)
| Increased Specific Gravity (usually 1.001-1.035)
Volume depletion
45
Urinalysis (Chemical Exam)
| Decreased Specific Gravity (usually 1.001-1.035)
Excessive fluid intake, diuretic therapy, or diabetes insipidus
46
Urinalysis (Chemical Exam)
Increased pH
(Usually 4.6-8.0)
vomiting, urination infections, or kidney disease
47
Urinalysis (Chemical Exam)
Decreased pH
(Usually 4.6-8.0)
Aspirin overdose, starvation, alcohol ingestion, high protein diet
48
Urinalysis (Chemical Exam)
| Protein presence
Glomerulonephritis, pre-eclampsia, complications from diabetes
49
Urinalysis (Chemical Exam)
| Glucose presence
diabetes, burns, pancreatitis, corticosteroid use, Cushing's disease
50
Urinalysis (Chemical Exam)
| Ketone presence
starvation, alcoholism, diabetic ketoacidosis (break down of fat stores)
51
Urinalysis (Chemical Exam)
| Bilirubin presence
Biliary obstruction and liver injury
52
Urinalysis (Chemical Exam)
| Blood presence
Kidney stones, urinary trauma, UTI, strenuous exercise, bladder cancer
53
Urinalysis (Chemical Exam)
| Leukocyte Esterase
UTI
| by product of neutrophils - high in bacterial infections
54
Urinalysis (Chemical Exam)
| Urobilinogen excess
hemolysis and hepatocellular disease
55
Urinalysis (Chemical Exam)
Nitrites
*shouldn't have them
Infection
| *some bacteria convert nitrates to nitrites
56
Urinalysis (Microscopic Exam)
| RBC and WBC count?
WBC: 0-5 per high power field
RBC: 0-3 per high power field
57
Bence Jones protein in urine
Multiple Myeloma
58
Crystals in urine
Kidney stones (cysteine, calcium, oxalate, struvite)
59
Casts (formed in distal convoluted tubule)
| RBC vs WBC?
RBC: glomerulonephritis
WBC: phelonephritis - (upper kidney infection)
60
Aspartate aminotransferase (AST)
Normal: 7-42 IU/liter
Elevated with:
liver, muscle or cardiac injury
61
```
Alanine aminotransferase (ALT)
Normal: 1-45 IU/liter
```
More sensitive for liver injury
62
Alkaline Phosphatase
Normal: 25-160 IU/L
Elevated with:
Bile duct obstruction
In liver: cholecystitis
Outside liver: viral hepatitis or cirrhosis
*could be associated with metastatic bone cancer
63
Gamma glutamyl transpeptidase (GGT)
| Elevated with:
liver injury, or biliary obstruction
| Marker of alcohol use***
64
Unconjugated bilirubin
| Elevation?
Bilirubin bound to albumin
Not water soluble
Elevated with hemolysis
65
Conjugated bilirubin
Bilirubin cleaved of albumin (occurs in liver)
Water soluble
Elevated with bile duct obstruction
66
Albumin
Marker of liver function
67
Prothrombin time (PT)
Normal 11.5-13.5 seconds
Monitored with:
Time required for coagulation to occur
Marker of liver function because clotting factors are produced in liver
Monitor in COUMADIN THERAPY (extrinsic clotting - factors I, II, V, VII, X)
68
Indications for coagulation studies
Unexplained bleeding/excessive bruising
Consecutive pregnancy loss
Patients receiving heparin or Coumadin therapy (blood thinning)
69
Partial thromboplastin time (aPTT)
Normal 27-38 seconds
Monitored with:
Heparin therapy
| Intrinsic clotting
70
Increased Amylase and lipase levels (pancreas enzymes)
Pancreatitis
Biliary Obstruction
Pancreatic Carcinoma
71
Lipase or Amylase: MORE specific for pancreatic inflammation
Lipase
Remains elevated longer
Norm:
72
Lipase or Amylase: LESS specific for pancreatic inflammation
Amylase
Peaks earlier and declines more rapidly
Norm: 10-130 U/L
73
Indications for ordering electrolytes
Pts receiving IV fluid;
Metabolic/endocrine abnormalities;
Meds that interfere with electrolytes;
Severe vomiting/diarrhea
74
Elevated Sodium
| Norm: 136-145 mmol/L)
Dehydration
Vomiting/diarrhea
Endocrine (SIADH, aldosteronism, diabetes inspidius)
75
Decreased Sodium
| Norm: 136-145 mmol/L)
```
Overhydration
Endocrine (Cushing's disease)
```
76
Elevated Potassium
| Norm: 3.5-5.0 mEq/L
Cell injury, kidney failure, endocrine disorders (addisons)
77
Decreased Potassium
| Norm: 3.5-5.0 mEq/L
Malnutrition, vomiting/diarrhea, diuretic medications
78
Elevated Chloride
| Norm: 97-107 mEq/L
dehydration, overactive parathyroid glands
79
Decreased Chloride
| Norm: 97-107 mEq/L
Vomiting (lost of gastric acid)
80
Elevated Magnesium
| Norm: 1.3-2.1 mg/dL
kidney disease
| use of antacids (M.O.M.)
81
Decreased Magnesium
| Norm: 1.3-2.1 mg/dL
```
Inadequate absorption (poor diet, alcoholism, diarrhea)
Diuretic medication
```
82
Metabolically active Calcium
IONIZED
| when bound to proteins it is not
83
Elevated calcium
| Norm: 8.2-10.2 mg/dL
Hyperparathyroid hormones
cancer
excessive Vit D
84
Decreased calcium
| Norm: 8.2-10.2 mg/dL
Hypoparathyroid hormones
Deficient protein
Vit. D deficiency
85
Elevated glucose in blood
diabetes, endocrine disorders, prednisone therapy, or pancreatitis
86
Hemoglobin A1C
Norm
87
Elevated Blood Urea Nitrogen (BUN)
Norm: 5-20 mg/dL
Kidney test
Impaired kidney function
88
Decreased Blood Urea Nitrogen (BUN)
Norm: 5-20 mg/dL
Kidney Test
```
Liver failure (less urea produced)
Malnutrition (less proteins)
Endocrine disorders (SIADH)
```
89
```
Elevated Creatinine (Cr)
Norm: Men (0.9-1.2); Women (0.6-1.1)
```
Impaired renal function
| Large muscle mass
90
```
Decreased Creatinine (Cr)
Norm: Men (0.9-1.2); Women (0.6-1.1)
```
Decreased muscle mass
| Liver disease
91
Elevated Uric Acid
| Norm: Men (3.4-8.0); Women (2.4-6 mg/dl)
excessive cell breakdown of nucleonic acids (gout)
excessive destruction of cells (leukemia)
inability to excrete uric acid (renal failure)
92
Hyperthyroidism
Elevated T4 and T3
| Decreased TSH
93
Hypothyroidism
Decreased T4 and T3
| Increased TSH
94
Blood culture when
bacteremia is present
95
Urine culture when
suspected UTI or pyelonephritis
96
Throat culture
Golf standard from streptococcal pharyngitis
97
Sputum culture
diagnosis and treatment of pneumonia and TB
98
Sedimentation rate (Sed rate)
Marker of inflammation
99
D-Dimer
Marker of clotting process
| Screen for VENOUS THROMBOSIS (DVT or PE)
100
Brain natriuretic peptide (BNP)
Increased with ventricular volume expansion and pressure overload
(Congestive heart failure)
