Lecture 4: Interpretation of Clinical Lab Values Flashcards

1
Q

___: substances whose chemical constituents are being identified and measured

A

Analytes

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2
Q

Lab assays to measure analyte level usually use ___ prepared from whole blood drawn

A

serum

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3
Q

____: the watery acellular portion of blood separated by centrifugation of whole blood in the presence of anticoagulant

A

Plasma

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4
Q

What type of solution is plasma? serum?

A

plasma: physiological solution
serum: non-physiological solution

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5
Q

____: liquid remaining after centrifugation of whole blood that has been allowed to clot

A

Serum

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6
Q

Major advantage of serum?

A

There are no additives required to prevent clotting

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7
Q

True or False: Careless handling of serum may result in RBC lysis

A

True

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8
Q

True or False: There is a small possibility of false positives with serum

A

True

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9
Q
A
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10
Q

Most diagnostically important enzymes have _____ functions and do not normally function in ___.

A

intracellular; blood

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11
Q

What are two reasons why blood from normal healthy individuals may contain enzymes?

A
  1. Active secretion (i.e., coagulation precursors such as prothrombin)
  2. Release from cells at LOW LEVELS during normal cell turnover.
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12
Q

True or False: In healthy individuals blood enzyme levels are fairly constant – equilibrium between release and removal

A

True

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13
Q

Where do most enzymes function?

A

In cells

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14
Q

True or False: Disease or exposures to drugs, microbes, can cause damage to cell membranes (cell necrosis) and lead intracellular enzymes to be released into the blood, causing elevated blood enzyme concentrations

A

True

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15
Q

True or False: Enzymes in blood due to cellular damage function physiologically

A

False - Enzymes in blood due to cellular damage function no longer function physiologically

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16
Q

True or False: Detection of elevated enzyme levels can help to: 1) make/confirm dx; 2) develop prognosis, 3) monitor response to drug therapy

A

True

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17
Q

Two clinical reasons for elevated enzymes in blood?

A

1) Basal (normal) levels
-normal cellular turnover

2) Pathologies, drugs
-can cause enzyme levels greater than (or sometimes less than) basal levels

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18
Q
A
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19
Q

1) Which of these enzymes is the MOST specific test?
2) Which of these enzymes is the LEAST specific test?
3) How might you improve diagnostic specificity?

A

1) ALT
2) LDH
3) Panels/profiles/isoforms

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20
Q

True or False:
Serum chemistry profiles are generated for patients to:
1) assess health status
2) provide baseline levels
3) monitor response to treatment, etc.

A

True

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21
Q

____: Series or panel of 8 chemical blood tests that assess fluid and electrolyte status, kidney function, blood sugar levels (Diabetes), malnutrition and
response to various medications and other therapies

A

Basic Metabolic Panel/Chem 7

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22
Q

True or False: A BMP may identify acute problems involving kidney, diabetic shock, respiratory
distress and congestive heart failure

A

True

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23
Q

What 8 chemical blood tests are done for a BMP?

A

-Serum Sodium
-Serum Potassium
-Serum Chloride
-Serum Calcium
-CO2
-Blood Urea Nitrogen (BUN)
-Creatinine
-Glucose

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24
Q

____: A panel of 14 chemical blood tests that adds assessment of liver function to the BMP.

A

CMP (Chem 12)

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25
Q

True or False: A CMP is used as routine test during physical exam or to monitor chronic conditions such as hypertension or diabetes or to monitor response to a drug regimen
that may have kidney- or liver-related adverse reactions

A

True

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26
Q

What 14 chemical blood tests are looked at in a CMP?

A
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27
Q

Renal Profile?

A
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28
Q

Liver Profile?

A
29
Q

Muscle Profile?

A
30
Q

The Comprehensive Metabolic Panel includes the
Basic Metabolic Panel tests and also assesses which
of the following organs?

A. Heart
B. Pancreas
C. Liver
D. Brain

A

C. Liver

31
Q

____: urea is a waste product of protein digestion; indicates kidney dysfunction

A

BUN (blood urea nitrogen)

32
Q

___: waste product of muscle contraction cleared by kidneys; indicates kidney dysfunction.

A

Creatine

33
Q

What does it mean if BUN/Creatinine ratio is >10:1 to 20:1?

A

Indicates poor blood flow to kidneys (i.e., congestive heart failure)

34
Q

_____: waste product of purine breakdown cleared by the kidneys; indicates hyperuricemia/gout and kidney disease

A

Uric Acid

35
Q

___, ___, and ___ assess biliary tract damage - cholestasis

A

ALK/ALP, GGT, 5’ NT

36
Q

____ assesses chronic decrease vs. acute (normal) liver damage

A

Albumin

37
Q

___, ____, and ___ assess hepatocellular damage

A

ALT, AST, and LDH

38
Q

True or False: Bilirubin (T-, D- and I-BIL) assesses heme degradation product diagnostic for liver function, hemolytic anemias

A

True

39
Q

Where is AST expressed?

A

AST: skeletal/cardiac muscle, liver

40
Q

____ is a non-specific test for muscle and heart damage

A

LDH

41
Q

___ is required for muscle cell function; after heart attack, strenuous exercise, muscle injury

A

Creatine kinase

42
Q

What 4 enzyme tests are used to evaluate pancreatic function (i.e., pancreatitis):

A

1) amylase
2) lipase
3) lipase:amylase ratio – possible differentiation of alcoholic vs. non-alcoholic acute pancreatitis
4) trypsinogen/Trypsin

43
Q

True or False: Prostate-specific antigen (PSA) – screening test for prostate cancer

A

True

44
Q

Which elevated serum test result paired with elevated AST levels would be the most specific diagnostic for liver disease?

A
45
Q

Which analyte is most likely to be elevated in a patient’s serum following a heart attack?

A. CK
B. BUN
C. Creatinine
D. Amylase

A

A. CK

46
Q

Elevated CK following a heart attack will most likely accompany elevated..

A. Albumin
B. BUN
C. AST
D. Lipase

A

C. AST

47
Q

____: the ability of test to actually measure what it claims to measure

____: the ability to reproducibly obtain the same result on the same patient sample.

A

Accuracy

Precision

48
Q

True or False: Accuracy is the sum of true positive results and true negative results divided by the total number of samples
tested.

A

True

49
Q

What type of distribution defines the reference range?

A

Gaussian Distribution

50
Q

In a normal population with Gaussian distribution ___% of individuals will be ±1 SD and ___% ±2 SD.

A

68%; 95%

51
Q

The reference range is the range of
values within__ SD of the mean,
which covers __ % of healthy
individuals

A

2 ; 95%

52
Q

True or False: Average total cholesterol in the U.S. is greater than the recommended levels (< 200 mg/dl) for decreased risk of heart disease,
which is determined epidemiologically.

A

True

53
Q

What 4 factors influence reference range?

A

1) Interlaboratory variation
2) “Normal” reference population is not really “normal”
3) Physiologic variation (age, biological sex, ethnicity, time of day, etc.)
4) Skewed “non-random” distribution of analyte values in reference population

54
Q

Isoenzymes or Isozymes are distinct variant forms of an enzyme. All isozymes of an enzyme catalyze the same ___ but differ slightly in what three ways?

A

reaction

1) amino acid composition
2) Cell- and tissue-type in which they function
3) Timing of expression

55
Q

True or False: LDH is a isoenzyme

A

True

56
Q

_____: catalyzes the reversible formation of lactate from pyruvate (pyruvate from lactate in the liver)

A

Lactate dehydrogenase (LDH)

57
Q

LDH is a ____(4 subunits) composed of various combinations of __ and __ subunits

A

tetramer
H; M

58
Q

True or False: LDH is a highly non-specific test in isolation (heart, liver, lungs, kidneys, sk.muscle, RBCs and lymphocytes); however, isozyme-specific tests are much more specific.

A

True

59
Q

If LDH-1:LDH-2 >1, what does this indicate?

If LDH-5:LDH-4 > 1, what does this indicate?

A

HEART damage

LIVER damage

60
Q

___ Isoenzymes are dimers composed of 2 __ monomers, 2 __ monomers, or one of each

A

CK Isoenzymes
B-monomers; M-monomers

61
Q

CK-BB (CK-1) is found in greatest abundance in the ___

Diagnostic value = ____

A

Brain

CNS damage

62
Q

CK-MB (CK-2) is found in greatest abundance in the ____

Diagnostic value = _____

A

myocardium

Diagnostic value = Acute myocardial infarction (AMI)

63
Q

CK-MM (CK-3) is found in greatest abundance in the ____ muscle

Diagnostic value = ____

A

skeletal muscle

Diagnostic value = skeletal muscle damage

64
Q

True or False: LDH and CK Isozymes in Heart Disease

A

True

65
Q

______heart attacks cause cardiomyocyte damage and release of cardiac enzymes into the blood.

A

Acute Myocardial Infarctions (AMI)

66
Q

Combination of ____ and ___ isozymes along with ___ and ___ are diagnostic for AMI

A

CK-MB; LDH-1; Troponins; Myoglobins

67
Q

Cardiac troponin exists as a complex of protein subunits:
___, ____, and ____

A

TnI, TnT, and TnC

68
Q

True or False: Troponin regulates Ca2+-mediated actin-myosin interactions during cardiac muscle contraction.

A

True

69
Q

Which LDH isozyme is the most specific diagnostic test for Liver damage?

A. LDH-1
B. LDH-2
C. LDH-3
D. LDH-4
E. LDH-5

A

E. LDH-5