Clinical Chemistry- Proteins, Electrophoresis, and Lipids Flashcards
1
Q
- Kjeldahl’s procedure for total protein is based
upon the premise that:
A. Proteins are negatively charged
B. The pKa of proteins is the same
C. The nitrogen content of proteins is constant
D. Proteins have similar tyrosine and tryptophan
content
A
C. The nitrogen content of proteins is constant
2
Q
- Upon which principle is the biuret method based?
A. The reaction of phenolic groups with CuIISO4
B. Coordinate bonds between Cu+2 and carbonyl
and imine groups of peptide bonds.
C. The protein error of indicator effect producing
color when dyes bind protein
D. The reaction of phosphomolybdic acid with
protein
A
B. Coordinate bonds between Cu+2 and carbonyl
and imine groups of peptide bonds.
3
Q
- Which statement about the biuret reaction for
total protein is true?
A. It is sensitive to protein levels below 0.1 mg/dL
B. It is suitable for urine, exudates, and transudates
C. Polypeptides and compounds with repeating
imine groups react
D. Hemolysis will not interfere
A
C. Polypeptides and compounds with repeating
imine groups react
4
Q
- Which of the following protein methods has the
highest analytical sensitivity?
A. Refractometry
B. Folin–Lowry
C. Turbidimetry
D. Direct ultraviolet absorption
A
B. Folin–Lowry
5
Q
- Which of the following statements regarding
proteins is true?
A. Total protein and albumin are about 10% higher
in ambulatory patients
B. Plasma total protein is about 20% higher than
serum levels
C. Albumin normally accounts for about one-third
of the cerebrospinal fluid total protein
D. Transudative serous fluid protein is about
two-thirds of the serum total protein
A
A. Total protein and albumin are about 10% higher
in ambulatory patients
6
Q
- Hyperalbuminemia is caused by:
A. Dehydration syndromes
B. Liver disease
C. Burns
D. Gastroenteropathy
A
A. Dehydration syndromes
7
Q
- High serum total protein but low albumin is
usually seen in:
A. Multiple myeloma
B. Hepatic cirrhosis
C. Glomerulonephritis
D. Nephrotic syndrome
A
A. Multiple myeloma
8
Q
- Which of the following conditions is most
commonly associated with an elevated level
of total protein?
A. Glomerular disease
B. Starvation
C. Liver failure
D. Malignancy
A
D. Malignancy
9
Q
- Which of the following dyes is the most specific
for measurement of albumin?
A. Bromcresol green (BCG)
B. Bromcresol purple (BCP)
C.Tetrabromosulfophthalein
D. Tetrabromphenol blue
A
B. Bromcresol purple (BCP)
10
Q
- Which of the following factors is most likely
to cause a falsely low result when using the
BCG dye-binding assay for albumin?
A. The presence of penicillin
B. An incubation time of 120 seconds
C. The presence of bilirubin
D. Lipemia
A
A. The presence of penicillin
11
Q
- At pH 8.6, proteins are _________ charged and
migrate toward the _________.
A. Negatively, anode
B. Positively, cathode
C. Positively, anode
D. Negatively, cathode
A
A. Negatively, anode
12
Q
- Electrophoretic movement of proteins toward the
anode will decrease by increasing the:
A. Buffer pH
B. Ionic strength of the buffer
C. Current
D. Voltage
A
B. Ionic strength of the buffer
13
Q
- At pH 8.6, the cathodal movement of γ globulins
is caused by:
A. Electroendosmosis
B. Wick flow
C. A net positive charge
D. Cathodal sample application
A
A. Electroendosmosis
14
Q
- Which of the following conditions will prevent
any migration of proteins across an electrophoretic
support medium such as agarose?
A. Using too high a voltage
B. Excessive current during the procedure
C. Loss of contact between a buffer chamber and
the medium
D. Evaporation of solvent from the surface of the
medium
A
C. Loss of contact between a buffer chamber and
the medium
15
Q
- Which of the following proteins has the highest pI?
A. Albumin
B. Transferrin
C. Ceruloplasmin
D. IgG
A
D. IgG
16
Q
- Which of the following proteins migrates in the
β region at pH 8.6?
A. Haptoglobin
B. Orosomucoprotein
C. Antichymotrypsin
D. Transferrin
A
D. Transferrin
17
Q
- Which of the following is one advantage of
high-resolution (HR) agarose electrophoresis
over lower-current electrophoresis?
A. High-resolution procedures detect monoclonal
and oligoclonal bands at a lower concentration
B. A smaller sample volume is used
C. Results are obtained more rapidly
D. Densitometric scanning of HR gels is more
accurate
A
A. High-resolution procedures detect monoclonal
and oligoclonal bands at a lower concentration
18
Q
- Which of the following conditions is associated
with “β-γ bridging”?
A. Multiple myeloma
B. Malignancy
C. Hepatic cirrhosis
D. Rheumatoid arthritis
A
C. Hepatic cirrhosis
19
Q
- Which support medium can be used to determine
the molecular weight of a protein?
A. Cellulose acetate
B. Polyacrylamide gel
C. Agar gel
D. Agarose gel
A
B. Polyacrylamide gel
20
Q
- Which of the following stains is used for
lipoprotein electrophoresis?
A. Oil Red O
B. Coomassie Brilliant Blue
C. Amido Black
D. Ponceau S
A
A. Oil Red O
21
Q
- Which of the following serum protein
electrophoresis results suggests an acute
inflammatory process?
A
C.
22
Q
- Which of the following conditions is usually
associated with an acute inflammatory pattern?
A. Myocardial infarction (MI)
B. Malignancy
C. Rheumatoid arthritis
D. Hepatitis
A
A. Myocardial infarction (MI)
23
Q
- The electrophoretic pattern shown in the following
densitometric tracing most likely indicates:
A. α1-Antitrypsin deficiency
B. Infection
C. Nephrosis
D. Systemic sclerosis
A
A. α1-Antitrypsin deficiency
24
Q
- What is the clinical utility of testing for serum
prealbumin?
A. Low levels are associated with increased free
cortisol
B. High levels are an indicator of acute
inflammation
C. Serial low levels indicate compromised
nutritional status
D. Levels correlate with glomerular injury in
patients with diabetes mellitus
A
C. Serial low levels indicate compromised
nutritional status
25
Q
- Which serum protein should be measured in a
patient suspected of having Wilson’s disease?
A. Hemopexin
B. Alpha-1 antitrypsin
C. Haptoglobin
D. Ceruloplasmin
A
D. Ceruloplasmin
26
Q
- A patient with hemolytic-uremic syndrome
associated with septicemia has a haptoglobin
level that is normal, although the plasma free
hemoglobin is elevated and hemoglobinuria is
present. Which test would be more appropriate
than haptoglobin to measure this patient’s
hemolytic episode?
A. Hemopexin
B. Alpha-1 antitrypsin
C. C-reactive protein
D. Transferrin
A
A. Hemopexin
27
Q
- Quantitative determination of Hgb A2 and Hgb F
are best performed by:
A. High-performance liquid chromatography
B. Alkali denaturation
C. Electrophoresis
D. Direct bichromatic spectrophotometry
A
A. High-performance liquid chromatography
28
Q
- Select the correct order of Hgb migration on
agarose or cellulose acetate at pH 8.6.
A. – C→F→S→A +
B. – S→C→A→F +
C. – C→S→F→A +
D. – S→F→A→C +
A
C. – C→S→F→A +
29
Q
- Which of the following abnormal types of Hgb
migrates to the same position as Hgb S on agarose
or cellulose acetate at pH 8.6?
A. Hgb C
B. Hgb DPunjab
C. Hgb OArab
D. Hgb E
A
B. Hgb DPunjab
30
Q
- Which Hgb is a β-δ chain hybrid and migrates to
the same position as Hgb S at pH 8.6?
A. Hgb CHarlem
B. HgbLepore
C. Hgb GPhiladelphia
D. Hgb DPunjab
A
B. HgbLepore
31
Q
- Select the correct order of Hgb migration on
citrate agar at pH 6.2.
A. – F→S→C→A +
B. – F→A→S→C +
C. – A→S→F→C +
D. – A→C→S→F +
A
B. – F→A→S→C +
32
Q
- Which Hgb separates from Hgb S on citrate (acid)
agar, but not agarose or cellulose acetate?
A. Hgb DPunjab
B. Hgb E
C. Hgb CHarlem (Georgetown)
D. Hgb OArab
A
A. Hgb DPunjab
33
Q
- Which statement best describes immunofixation
electrophoresis (IEF)?
A. Proteins are separated by electrophoresis
followed by overlay of monospecific
anti-immunoglobulins
B. Proteins react with monospecific antisera
followed by electrophoresis
C. Antisera are electrophoresed, then diffused
against patient’s serum
D. Serum is electrophoresed; the separated
immunoglobulins diffuse against specific
antisera placed into troughs
A
A. Proteins are separated by electrophoresis
followed by overlay of monospecific
anti-immunoglobulins
34
Q
- In double immunodiffusion reactions, the
precipitin band is:
A. Invisible before the equivalence point is reached
B. Concave to the protein of greatest molecular
weight
C. Closest to the well containing the highest level of
antigen
D. Located in an area of antibody excess
A
B. Concave to the protein of greatest molecular
weight
35
Q
- Which of the following statements regarding the
identification of monoclonal proteins by IFE is
true?
A. The monoclonal band must be present in the
γ region
B. When testing for a monoclonal gammopathy,
both serum and urine must be examined
C. A diagnosis of monoclonal gammopathy is based
upon quantitation of IgG, IgA, and IgM
D. A monoclonal band always indicates a malignant
disorder
A
B. When testing for a monoclonal gammopathy,
both serum and urine must be examined
36
Q
- Which of the following statements regarding
paraproteins is true?
A. Oligoclonal banding is seen in the CSF of greater
than 90% of multiple sclerosis cases
B. The Bence–Jones protein heat test is
confirmatory for monoclonal light chains
C. Light chains found in urine are always derived
from monoclonal protein
D. The IgA band is usually cathodal to the IgG
precipitin band
A
A. Oligoclonal banding is seen in the CSF of greater
than 90% of multiple sclerosis cases
37
Q
- Which statement regarding IFE is true?
A. Serum containing a monoclonal protein should
have a κ:λ ratio of 0.5
B. A monoclonal band seen with monospecific
antiserum should not be visible in the lane where
polyvalent antiserum or sulfosalicylic acid was
added
C. CSF should be concentrated 50- to100-fold
before performing IFE
D. When oligoclonal bands are seen in the CSF,
they must also be present in serum to indicate
multiple sclerosis
A
C. CSF should be concentrated 50- to100-fold
before performing IFE
38
Q
- Which test is the most sensitive in detecting early
monoclonal gammopathies?
A. High-resolution serum protein electrophoresis
B. Urinary electrophoresis for monoclonal light
chains
C. Capillary electrophoresis of serum and urine
D. Serum-free light chain immunoassay
A
D. Serum-free light chain immunoassay
39
Q
- Which test is the most useful way to evaluate the
response to treatment for multiple myeloma?
A. Measure of total immunoglobulin
B. Measurement of 24-hour urinary light chain
concentration (Bence–Jones protein)
C. Capillary electrophoresis of M-protein recurrence
D. Measurement of serum-free light chains
A
D. Measurement of serum-free light chains
40
Q
- Which of the following is more commonly
associated with a nonmalignant form of
monoclonal gammopathy (MGUS)?
A. Bone marrow plasma cells comprise 20% of
nucleated cells
B. Monoclonal protein (M-protein) concentration
is 3.5 g/dL
C. M-protein is IgG
D. Age greater than 60 at the time of monoclonal
protein discovery
A
D. Age greater than 60 at the time of monoclonal
protein discovery
41
Q
- Capillary electrophoresis differs from agarose gel
electrophoresis in which respect?
A. A stationary support is not used
B. An acidic buffer is used
C. A low voltage is used
D. Electroendosmosis does not occur
A
A. A stationary support is not used
42
Q
- Select the order of mobility of lipoproteins
electrophoresed on cellulose acetate or agarose at pH 8.6.
A. – Chylomicrons→pre-β →β→α+
B. – β→pre-β→α→chylomicrons +
C. – Chylomicrons →β→pre-β→α +
D. – α→β→pre-β→chylomicrons +
A
C. – Chylomicrons →β→pre-β→α +
43
Q
- Following ultracentrifugation of plasma, which
fraction correlates with pre-β lipoprotein?
A. Very low-density lipoprotein (VLDL)
B. Low-density lipoprotein (LDL)
C. High-density lipoprotein (HDL)
D. Chylomicrons
A
A. Very low-density lipoprotein (VLDL)
44
Q
- Select the lipoprotein fraction that carries most of
the endogenous triglycerides.
A. VLDL
B. LDL
C. HDL
D. Chylomicrons
A
A. VLDL
45
Q
- The protein composition of HDL is what
percentage by weight?
A. Less than 2%
B. 25%
C. 50%
D. 90%
A
C. 50%
46
Q
- Which apoprotein is inversely related to risk of
coronary heart disease?
A. Apoprotein A-I
B. Apoprotein B100
C. Apoprotein C-II
D. Apoprotein E4
A
A. Apoprotein A-I
47
Q
- In familial β dyslipoproteinemia (formerly
type III hyperlipoproteinemia), which lipoprotein
accumulates?
A. Chylomicrons
B. VLDL
C. IDL
D. VLDL
A
C. IDL
48
Q
- Which of the following mechanisms accounts
for the elevated plasma level of β lipoproteins
seen in familial hypercholesterolemia (formerly
type II hyperlipoproteinemia)?
A. Hyperinsulinemia
B. ApoB-100 receptor defect
C. ApoC-II activated lipase deficiency
D. ApoE3 deficiency
A
B. ApoB-100 receptor defect
49
Q
- Which enzyme deficiency is most commonly
associated with familial hypertriglyceridemia
associated with fasting plasma cholomicrons
(formerly type I hyperlipoproteinemia)?
A. β Glucocerebrosidase deficiency
B. Post–heparin-activated lipoprotein lipase
deficiency
C. Apo-B deficiency
D. Apo-C-III deficiency
A
B. Post–heparin-activated lipoprotein lipase
deficiency
50
Q
- Which of the following conditions is most
consistently associated with secondary
hypercholesterolemia?
A. Hypothyroidism
B. Pancreatitis
C. Oral contraceptive therapy
D. Diabetes mellitus
A
A. Hypothyroidism
51
Q
- Which of the following is associated with Tangier
disease?
A. Apoprotein C-II deficiency
B. Homozygous apo-B100 deficiency
C. Apoprotein C-II activated lipase
D. Apoprotein A-I deficiency
A
D. Apoprotein A-I deficiency
52
Q
- Which of the following statements is correct?
A. Both HDL and LDL are homogenous
B. There are several subfractions of LDL but
not HDL
C. There are several subfractions of HDL but
not LDL
D. There are several subfractions of both HDL
and LDL
A
D. There are several subfractions of both HDL
and LDL
53
Q
- What is the lipid testing protocol for adults
recommended by the National Cholesterol
Education Program (NCEP) to evaluate risk for
atherosclerosis beginning at age 20?
A. Total cholesterol, fasting or nonfasting every year
B. Total cholesterol, fasting, every 2 years
C. Lipid profile, fasting, every 5 years
D. LDL cholesterol, fasting, every 2 years
A
C. Lipid profile, fasting, every 5 years
54
Q
- What is the most appropriate fasting procedure
when a lipid study of triglyceride, total cholesterol,
HDL cholesterol, and LDL cholesterol tests are
ordered?
A. 8 hours; nothing but water allowed
B. 10 hours; water, smoking, coffee, tea (no sugar
or cream) allowed
C. 12 hours; nothing but water allowed
D. 16 hours; water, smoking, coffee, tea (no sugar
or cream) allowed
A
C. 12 hours; nothing but water allowed
55
Q
- Treatment recommendations for patients with
coronary heart disease are based upon
measurement of which analyte?
A. HDL cholesterol
B. Apo-B100
C. LDL cholesterol
D. Total cholesterol
A
C. LDL cholesterol
56
Q
- What is the HDL cholesterol cutpoint recommend
by NCEP?
A. <30 mg/dL
B. <40 mg/dL
C. <30 mg/dL for males and < 40 mg/dL
for females
D. <45 mg/dL for males and < 50 mg/dL
for females
A
B. <40 mg/dL
57
Q
- An EDTA blood sample is collected from a
nonfasting person for a CBC. The physician
collected the sample from the femoral vein because
venipuncture from the arm was unsuccessful. He
called the lab 15 minutes after the sample arrived
and requested a lipid study including triglyceride,
total cholesterol, HDL cholesterol, and LDL
cholesterol. Which test results should be used to
evaluate the patient’s risk for coronary artery
disease?
A. Total cholesterol and LDL cholesterol
B. LDL cholesterol and triglyceride
C. Total cholesterol and HDL cholesterol
D. Total cholesterol and triglyceride
A
C. Total cholesterol and HDL cholesterol
58
Q
- Which of the following diseases is caused by a
deficiency of sphingomyelinase?
A. Gaucher disease
B. Fabry disease
C. Niemann–Pick disease
D. Tay–Sachs disease
A
C. Niemann–Pick disease
59
Q
- Which method is considered the candidate
reference method for triglyceride measurement?
A. Glycerol kinase-ultraviolet
B. CDC modification of van Handel and Zilversmit
C. Hantzsch condensation
D. Glycerol kinase coupled to peroxidase
A
B. CDC modification of van Handel and Zilversmit
60
Q
- Which of the following enzymes is common to all
enzymatic methods for triglyceride measurement?
A. Glycerol phosphate oxidase
B. Glycerol phosphate dehydrogenase
C. Glycerol kinase
D. Pyruvate kinase
A
C. Glycerol kinase
61
Q
- Select the reagent needed in the coupling enzyme
reaction used to generate a colored product in the
cholesterol oxidase method for cholesterol.
A. Cholestahexaene
B. H2O2
C. 4-Aminoantipyrine
D. Cholest-4-ene-3-one
A
C. 4-Aminoantipyrine
62
Q
- What is the purpose of the saponification step used
in the Abell–Kendall method for cholesterol
measurement?
A. Remove phospholipids
B. Reduce sterol molecules structurally similar to
cholesterol
C. Convert cholesterol esters to free cholesterol
D. Remove proteins that can interfere with color
formation
A
C. Convert cholesterol esters to free cholesterol
63
Q
- Which of the following methods for HDL
cholesterol is the reference method?
A. Manganese–heparin
B. Magnesium–phosphotungstate
C. Magnesium–dextran
D. Ultracentrifugation
A
D. Ultracentrifugation
64
Q
- Cholesterol esterase is used in enzymatic assays to:
A. Oxidize cholesterol to form peroxide
B. Hydrolyze fatty acids bound to the third carbon
atom of cholesterol
C. Separate cholesterol from apoproteins A-I
and A-II by hydrolysis
D. Reduce NAD+ to NADH
A
B. Hydrolyze fatty acids bound to the third carbon
atom of cholesterol
65
Q
- Which of the following reagents is used in the
direct HDL cholesterol method?
A. Sulfated cyclodextrin
B. Magnesium sulfate and dextran sulfate
C. Anti-apoA-I
D. Manganese heparin
A
A. Sulfated cyclodextrin
66
Q
- What do “direct” or homogenous methods for
LDL cholesterol assay have in common?
A. They are inaccurate when plasma triglyceride is
above 250 mg/dL
B. All use a detergent to facilitate selective reactivity
with reagent enzymes
C. All use monoclonal antibodies to apo A1 and C
D. All are free of interference from abnormal
lipoproteins
A
B. All use a detergent to facilitate selective reactivity
with reagent enzymes
67
Q
- Lipoprotein (a), or Lp(a), is significant when
elevated in serum because it:
A. Is an independent risk factor for atherosclerosis
B. Blocks the clearance of VLDLs
C. Displaces apo-AI from HDLs
D. Is linked closely to a gene for obesity
A
A. Is an independent risk factor for atherosclerosis
68
Q
- Which type of dietary fatty acid is not associated
with an increase in serum LDL cholesterol
production?
A. Monounsaturated trans fatty acids
B. Saturated fatty acids
C. Monounsaturated cis fatty acids
D. Monounsaturated trans Ω-9 fatty acids
A
C. Monounsaturated cis fatty acids
69
Q
- SITUATION: A lipemic specimen collected from
an adult after a 12-hour fast was assayed for total
cholesterol, triglycerides, and HDL cholesterol
using a direct HDL method.
Following are the results:
Total cholesterol = 220 mg/dL
HDL cholesterol = 40 mg/dL
Triglyceride = 420 mg/dL
The physician requests an LDL cholesterol assay
after receiving the results. How should the LDL
cholesterol be determined?
A. Dilute the specimen 1:10 and repeat all tests;
calculate LDL cholesterol using the Friedewald
equation
B. Perform a direct LDL cholesterol assay
C. Ultracentrifuge the sample and repeat the HDL
cholesterol on the infranate. Use the new result
to calculate the LDL cholesterol
D. Repeat the HDL cholesterol using the
manganese heparin precipitation method. Use
the new result to calculate the LDL cholesterol
A
B. Perform a direct LDL cholesterol assay
70
Q
- A person has a fasting triglyceride level of
240 mg/dL. The physician wishes to know the
patient’s non-HDL cholesterol level. What
cholesterol fractions should be measured?
A. Total cholesterol and HDL cholesterol
B. Total cholesterol and LDL cholesterol
C. HDL cholesterol and LDL cholesterol
D. Total cholesterol and chylomicrons
A
A. Total cholesterol and HDL cholesterol
