Lecture 2 Flashcards
1
Q
Where multiple tests are grouped as a single profile for ease of ordering since this group of tests are often all medically necessary.
Grouped to test specific systems.
A
Lab test panel
2
Q
A chemistry panel that includes electrolytes and tests of kidney function.
A
Basic Metabolic Panel (BMP)
3
Q
What’s included in a BMP?
A
Sodium Potassium Chloride Carbon dioxide content Blood Urea Nitrogen (BUN) Serum Creatinine (Cr) Serum glucose (Glu) Total Calcium
4
Q
What tubes can a BMP be collected in?
A
Light Green PST
Gold SST
Red
5
Q
Together with chloride, this molecule makes the major contribution to the plasma osmotic pressure.
A
Sodium (major cation in the extracellular space)
6
Q
Increased serum sodium level = ________ ?
A
Hypernatremia - This always indicates a relative total body water deficit, regardless of the extracellular volume status.
7
Q
Decreased serum sodium level = ________ ?
A
Hyponatremia - This always indicates a relative total body water excess, from excess water ingestion or inability of the kidney to excrete a sufficiently dilute urine, regardless of the extracellular volume status.
8
Q
Major intracellular cation.
A
Potassium
9
Q
Helps maintain the body’s balance of fluids; also important in muscle and nerve function.
A
Potassium
10
Q
What does hyperkalemia lead to?
A
Leads to aldosterone secretion and potassium excretion.
11
Q
What does hypokalemia lead to?
A
Leads to excretion of urine nearly devoid of potassium.
12
Q
Can indicate a primary and secondary hypoaldosteronism.
A
Hyperkalemia
13
Q
Can indicate diabetes mellitus, Cushing syndrome, hyperaldosteronism.
A
Hypokalemia
14
Q
Usually part of shifts in sodium or bicarbonate to maintain electrical neutrality.
A
Hyperchloremia and hypochloremia
15
Q
Indicates a metabolic alkalosis, either primary or secondary to a respiratory acidosis.
A
Increased bicarbonate
16
Q
Indicates the presence of a metabolic acidosis.
A
Decreased bicarbonate
17
Q
Formed in the liver as the end product of protein metabolism and is transported to the kidneys for excretion.
A
Urea
18
Q
When the BUN is interpreted in conjunction with the creatinine test, these tests are referred to as what?
A
Renal function studies
19
Q
What does an increase in urea nitrogen in the blood indicate?
A
An increase indicates decreased glomerular filtration and/or increased tubular reabsorption.
Inadequate excretion or increased production in the gut from ingested protein or blood.
20
Q
Excreted entirely by the kidneys and blood levels are therefore proportional to renal and excretory function.
A
Creatinine and BUN
21
Q
Total serum calcium is a measure of what 2 things?
A
Free ionized calcium and protein bound (usually to albumin) calcium.
Therefore, the total serum calcium level is affected by changes in serum albumin.
22
Q
As a rule of thumb, the total serum calcium level decreases by approximately ____mg for every ___g decrease in the serum albumin level.
A
0.8mg
1 gram
23
Q
Under the control of PTH, the plasma level of calcium varies with what 2 things?
A
Rate of calcium absorption from the small intestine and the proximal renal tubular reabsorption rate.
24
Q
Measures amount of nitrogen in the blood in the form of urea (renal function).
A
BUN
25
Break down product of creatine phosphate in muscle (renal function).
Creatinine
26
Simple carbohydrate used as an energy source. Eating or fasting affects the result (diabetes).
Glucose
27
Extracellular anion that maintains the body's acid base balance and facilitates oxygen/carbon dioxide exchanges by RBCs.
Chloride
28
Intracellular cation that maintains the body's acid base balance and affects neuromuscular function and cardiac muscle contraction and conductivity.
Potassium
29
Extracellular cation that determines fluid volum in the body and facilitates nerve conduction and neuromuscular function.
Sodium
30
If a patient has mild hypocalcemia, what other test would you order?
Serum albumin (if serum albumin level is low, this would affect the total serum calcium level).
31
Comprises about 60% of the total protein within the extracellular portion of the blood.
Transports many important blood constituents (drugs, hormones, enzymes).
Albumin
32
Where is albumin synthesized?
In the liver (hepatocytes) and is therefore a measure of hepatic function.
33
This enzyme occurs mostly in hepatocytes with smaller quantities in skeletal and heart muscle. It is released into circulation when cells are damaged or necrotic.
Increased levels usually indicate damage to the liver, although severe damage to skeletal muscle can produce significant elevations.
Alanine aminotransferase (ALT)
34
An enzyme present in a number of tissues, including the liver, bone, kidney, intestine, and placenta, each of which contains distinct isozyme forms.
The two major circulating alkaline phosphatase isoenzymes are bone and liver. Therefore elevation in the serum is most commonly a reflection of liver or bone disorders.
Alkaline phosphatase (ALP)
35
An enzyme that is present in hepatocytes and myocytes (both skeletal muscle and cardiac).
Elevations are most commonly a reflection of liver injury.
Aspartate Aminotransferase (AST)
36
When AST is more than 2x the ALT, what should you suspect?
Alcohol abuse with cirrhosis or alcoholic hepatitis
37
Normally the unconjugated bilirubin makes up _____ - _____% of the total bilirubin.
70-85%
38
Total protein measures 2 classes of protein. What are they?
Albumin and globulin
39
Increases or decreases in ___________ represent a balance between synthesis and protein catabolism.
Protein serum
40
Where is albumin synthesized?
Liver
41
What synthesizes immunoglobulins?
Mature plasma cells
42
Enzyme found in highest amounts in the liver.
ALT
43
Enzyme found in almost all body tissues; high amounts are found in the liver, bile ducts, and bone.
ALP
44
Enzyme found in high amounts in heart muscle, liver, and skeletal muscle.
AST
45
Yellowish pigment found in bile.
Bilirubin
46
Measures two classes of protein - albumin and globulin.
Total protein
47
How often are CBC tests available for hospitalized patients?
24/7
48
Unacceptable CBC specimen?
Clotted or greater than 48 hours
49
Count of the number of circulating red blood cells in 1mm cubed of peripheral venous blood.
Total red blood cell count
50
Normal total RBC count for male and female?
Male - 4.7 to 5.5 x 10^6 cells/mcL
Female - 3.5 to 5.5 x 10^6 cells/mcL
51
A decrease in Hgb concentration indicates..?
Anemia
52
An increase in Hgb concentration indicates...?
Polycythemia
53
Hgb values should be reviewed in conjugation with what other value?
Hematocrit
54
A measure of the percentage of the total blood volume that is made up by the RBCs.
Abnormal counts are counts by anemia, bleeding, RBC destruction, leukemia, malnutrition, overhydration.
Hematocrit
55
The amount of Hgb present in one cell.
MCH (mean corpuscular hemoglobin)
56
The proportion of each cell occupied by Hgb.
MCHC (mean corpuscular hemoglobin concentration)
57
Average size of RBCs.
MCV (mean corpuscular volume)
Low MCV - microcytic
Normal MCV - normocytic
High MCV - macrocytic
Helps to diagnose specific type of anemia.
58
And indication of the variation in the RBC size and referred to anisocytosis.
RDW (RBC distribution width)
59
Normal WBC count?
4,500-11,000/mm^3
60
And increase in WBC count (leukocytosis, greater than 11,000) can be caused by..?
```
Infections
Leukemia
Pregnancy
Neoplasms
Pneumonia
Inflammation
Tissue necrosis
```
61
A decrease in WBC count (leukopenia, less than 4,500) can be caused by..?
```
Bone marrow failure
Radiation
Chemotherapy
HIV infection
Viral disorders
```
62
Normal platelet count?
150,000 to 400,000/uL
63
An increase in platelet count, thrombocytosis (greater than 1 mil) can be caused by?
```
Bone marrow disorder
Acute bleeding
Exercise
Heart attack
Infections
Splenectomy
Surgery
```
64
A decrease in platelet count, thrombocytopenia (less than 150,000/uL) can be caused by?
```
Autoimmune disease
Medications
Alcohol
Viruses
Cancer
Anemia
```
65
Red blood cell count determines anemia.
RBC
66
Measures the functional status of the immune system.
WBC count
67
The percent by volume of packed RBCs in a whole blood sample.
Hematocrit (Hct)
68
Protein in RBCs that carries oxygen.
Hemoglobin (Hgb)
69
Responsible for blood clotting.
Platelets
70
Hct/RBC
MCV
71
Hgb/RBC
MCH
72
Hgb/Hct
MCHC (mean corpuscular hemoglobin concentration)
73
Measures deviation of the volume of RBCs
RDW
74
When a WBC count is abnormal, a CBC + differential is ordered. Describe this test..
When a differential is ordered, the percentage of each type of leukocyte present in a specimen is measured. WBC differentials are either performed manually or by an automated instrument.
75
Polymorphonuclear leukocytes mature phagocytes that migrate through tissues to destroy microbes.
Segmented neutrophils
76
Peripheral leukocytes. The nucleus forms a "U" or curled rod prior to segmentation.
Band form neutrophil
77
Granulocytes that participate in immediate hypersensitivity reactions.
Basophils
78
Mature granulocytes that respond to parasitic infections and allergic conditions.
Eosinophils
79
Type of WBC
Large - NK cells
Small - T and B cells
Lymphocytes
80
Large mononuclear phagocytes of the peripheral blood - immature stage of the macrophage.
Monocytes
81
A group of 10 chemical tests used to detect UTIs as we as metabolic and kidney disorders.
Urinalysis panel
82
What are the 10 chemical tests in the urinalysis panel?
```
Specific gravity
pH
Protein
Glucose
Ketones
Blood
Leukocyte esterase
Nitrite
Bilirubin
Urobilinogen
```
83
This is a sum of your blood's cholesterol content.
Total Cholesterol
84
This type of cholesterol helps carry away LDL cholesterol, thus keeping arteries open and your blood flowing more freely.
HDL cholesterol
85
Too much of this cholesterol in your blood causes the buildup of fatty deposits (plaques) in your arteries (atherosclerosis), which reduces blood flow. Thee plaques sometimes rupture and can lead to a heart attack or stroke.
LDL cholesterol
86
When you eat, your body converts any calories it doesn't need into this type of fat which are stored in fat cells.
Triglycerides
87
A steroid used to produce hormones and cell membranes.
Cholesterol
88
Carries fat from the liver to other parts of the body.
LDL
89
Binds fat in the blood stream and transport to liver for disposal.
HDL
90
Distributes triglycerides produces by the liver.
VLDL
91
A type of fat the body uses to store energy and give energy to muscles.
Triglycerides
92
How often should you perform a lipid panel on healthy adults?
Every 5 years - total cholesterol (don't need to include full panel)
93
If a specimen is hemolyzed (such as by a traumatic venipuncture or drawing blood with a needle that is too small) potassium levels may be falsely elevated. Why?
There are high concentrations of K in RBCs. If RBCs are lysed during phlebotomy, K is released into the serum resulting in elevated measured levels.
94
Which panel is appropriate for screening a patient for anemia?
Complete Blood Count
95
Which panel will provide you with electrolyte results?
BMP
96
Which panel is appropriate for initially screening a patient for diabetes?
Only need glucose level
97
What are the 3 analytical phases of testing?
Pre-analytical (pre-exam)
- provider orders correct test, proper specimen.
Analytical (examination)
- lab: ensures valid result
Post analytical (post-exam)
- lab: provides correct data
- provider: properly interprets data and takes action.
98
Which phase of testing accounts for up to 70% of all lab errors?
Pre-analytical
99
What are some examples of potential sources of errors during the pre-analytical phase?
```
Improperly ordered tests
Sample misidentification
Improper timing
Improper fasting
Improper anticoagulant to blood ratio
Improper mixing
Incorrect order of draw
Hemolyzed or lipemic specimens
```
Most frequent errors:
- Improperly filling the sample tube
- Placing specimens in wrong containers or preservatives
- Selecting incorrect test
100
What is the error rate for the analytical phase?
3.2 sigma performance (95%)
101
What are 3 examples of quality controls in place during the analytic phase of testing?
- Hematology analyzer (quantitative report) - high, medium, and low controls run every 8 hour shift for calibration.
- All critical range tests are repeated before submitting results.
- Manual testing results are reviewed by peer/supervisor before submitting results.
102
During the analytical phase, describe random vs. systematic error.
Random errors in experimental measures are caused by unknown and unpredictable changes in the experiment. These changes may occur in the measuring instruments or in the environmental conditions.
Systematic errors in experimental observations usually come from the measuring instruments. They may occur because there is something wrong with the instrument or its data handling system, or because the instrument is wrongly used by the experimenter.
103
How fast must a critical test value be reported?
Within 1 hour of completion to ordering provider.
104
How fast must a STAT test result be reported?
Must be reported within 1 hour of RECEIPT (usually telephone if critical).
105
Post analytical add on tests - "additional tests" requested after a specimen has been previously collected - give 3 problem examples of why..
Quantity insufficient
Degradation of the analyze (glucose degradation, storage temp)
Different anticoagulant or additive (red top specimen originally collected, new test requires purple top specimen.
106
What are 3 examples of post analytic reflex tests?
Screening and confirmatory tests
- HIV (ELISA + Western Blot)
- Syphilis (RPR + MHA-TP)
Hepatitis
- Acute virus hepatitis panel (positive result) + identifying hepatitis test.
Urinalysis
- Dipstick + Culture
107
What are 7 physiological pre collection variables?
1. Diurnal variation - AM vs PM.
2. Exercise
3. Diet
4. Stress
5. Posture
6. Age
7 Gender
108
What are the 3 interference pre-collection variables?
Hemolysis
Hemoconcentration - increases concentration of serum enzymes, proteins, and protein bound substances, including cholesterol, calcium, and triglycerides, as plasma water leaves the vein due to back pressure.
Hemodilution - when a standing patient reclines, extravascular water transfers to the vascular system and dilutes nondiffusible plasma constituents (20 min = 10% decrease).
109
Improperly timed specimens/delayed delivery to the lab...is error pre, analytic, or post?
Pre
110
If tube is put on the wrong analyzer, is the error a pre, analytic, or post?
Analytical
