A 64-year-old woman has IgA lambda myeloma. At diagnosis, SPEP showed a 28 g/L band in the beta region, typed as IgA lambda by immunofixation. After four cycles of a regimen that includes daratumumab, a therapeutic IgG1 kappa monoclonal antibody, the beta-region band has gone. A new faint band of about 1 g/L is now seen in the gamma region, and immunofixation types it as IgG kappa. She feels well, the serum free light chain ratio has returned to normal, and she has not had a stem cell transplant. All her samples are serum from fully clotted tubes. The new band most likely comes from:

Daratumumab, the therapeutic antibody itself

Oligoclonal immune reconstitution bands

Fibrinogen left in an unclotted sample

Relapse of her original myeloma clone

A 31-year-old woman has had pneumonia twice and frequent sinusitis over 5 years. Results: total protein 58 g/L (5.8 g/dL) (reference 60-80 g/L); albumin 42 g/L (4.2 g/dL) (reference 35-50 g/L); reference A/G ratio 1.1-2.2. SPEP shows normal-looking albumin, alpha and beta bands, a very faint gamma zone and no discrete band. Immunoglobulins: IgG 2.4 g/L (reference 7-16), IgA below 0.1 g/L (0.7-4.0), IgM 0.2 g/L (0.4-2.3). The serum free light chain kappa/lambda ratio is 1.0 (reference 0.26-1.65), and urine immunofixation shows no free light chains. What is her A/G ratio, and which conclusion fits best?

2.6; a primary antibody deficiency such as CVID

0.72; a primary antibody deficiency such as CVID

2.6; light chain myeloma suppressing normal immunoglobulins

0.38; nephrotic syndrome with urinary loss of IgG

A 70-year-old man has had vomiting and diarrhea for 3 days; the tourniquet was on for under a minute. Total protein 88 g/L (reference 60-80), albumin 52 g/L (35-50), urea 14.5 mmol/L (2.5-7.8), creatinine 118 µmol/L (60-110). SPEP shows all fractions raised in proportion, with no band. The most likely explanation is:

Hemoconcentration from fluid loss

An acute phase response to infection

Polyclonal hypergammaglobulinemia

In the biuret method for serum total protein, the violet color forms when:

Cupric ions bind peptide bonds in alkaline solution

An anionic dye binds to basic groups on albumin

Folin phenol reagent is reduced by tyrosine residues

Ninhydrin reacts with free alpha-amino groups

Plasma proteins and protein electrophoresis

23 DOH Abu Dhabi (HAAD) lab licensing practice questions on Plasma proteins and protein electrophoresis, part of Clinical Chemistry. The first 23 are below; the first 5 with answers and explanations (tap Show answer after you have chosen), the rest in Learn with a free account.

Question 1 · Hard
A 64-year-old woman has IgA lambda myeloma. At diagnosis, SPEP showed a 28 g/L band in the beta region, typed as IgA lambda by immunofixation. After four cycles of a regimen that includes daratumumab, a therapeutic IgG1 kappa monoclonal antibody, the beta-region band has gone. A new faint band of about 1 g/L is now seen in the gamma region, and immunofixation types it as IgG kappa. She feels well, the serum free light chain ratio has returned to normal, and she has not had a stem cell transplant. All her samples are serum from fully clotted tubes. The new band most likely comes from:
1. ADaratumumab, the therapeutic antibody itself
2. BOligoclonal immune reconstitution bands
3. CFibrinogen left in an unclotted sample
4. DRelapse of her original myeloma clone
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Answer: A · Daratumumab, the therapeutic antibody itself
Daratumumab is a human IgG1 kappa monoclonal antibody, and at therapeutic concentrations it can appear on SPEP and immunofixation as a small IgG kappa band. Her own clone is IgA lambda, so a band with a different heavy and light chain cannot be a relapse of that clone, and the normal free light chain ratio supports a response. Immune reconstitution bands are usually several small bands after intensive therapy such as transplant, and fibrinogen does not react with anti-IgG or anti-kappa and is absent from properly clotted serum. A daratumumab-specific immunofixation reflex assay, in which an anti-daratumumab antibody shifts the drug's band, confirms the cause. Without this check, the drug band could wrongly prevent a complete response from being recorded.
- B: Reconstitution bands usually follow transplant and are often several, not one IgG kappa band during daratumumab.
- C: Fibrinogen does not type as IgG kappa and is absent from clotted serum.
- D: Her clone is IgA lambda, so a new IgG kappa band is not the original clone.
Question 2 · Hard
A 31-year-old woman has had pneumonia twice and frequent sinusitis over 5 years. Results: total protein 58 g/L (5.8 g/dL) (reference 60-80 g/L); albumin 42 g/L (4.2 g/dL) (reference 35-50 g/L); reference A/G ratio 1.1-2.2. SPEP shows normal-looking albumin, alpha and beta bands, a very faint gamma zone and no discrete band. Immunoglobulins: IgG 2.4 g/L (reference 7-16), IgA below 0.1 g/L (0.7-4.0), IgM 0.2 g/L (0.4-2.3). The serum free light chain kappa/lambda ratio is 1.0 (reference 0.26-1.65), and urine immunofixation shows no free light chains. What is her A/G ratio, and which conclusion fits best?
1. A2.6; a primary antibody deficiency such as CVID
2. B0.72; a primary antibody deficiency such as CVID
3. C2.6; light chain myeloma suppressing normal immunoglobulins
4. D0.38; nephrotic syndrome with urinary loss of IgG
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Answer: A · 2.6; a primary antibody deficiency such as CVID
Globulin = total protein - albumin = 58 - 42 = 16 g/L, so A/G = 42 ÷ 16 = 2.6, above the reference range because globulin is low. The faint gamma zone and the low IgG, IgA and IgM show that the missing globulin is immunoglobulin, and recurrent bacterial chest and sinus infections in a young adult fit a primary antibody deficiency such as common variable immunodeficiency (CVID). Light chain myeloma can also suppress normal immunoglobulins, but a normal free light chain ratio and no urine free light chains argue strongly against it. Nephrotic syndrome would lower albumin, which is normal here. The value 0.38 is globulin divided by albumin, and 0.72 is albumin divided by total protein.
- B: 0.72 is albumin divided by total protein, not by globulin.
- C: A normal free light chain ratio and no urine free light chains argue against light chain myeloma.
- D: 0.38 is the ratio inverted, and her normal albumin excludes nephrotic syndrome.
Question 3 · Hard
A 70-year-old man has had vomiting and diarrhea for 3 days; the tourniquet was on for under a minute. Total protein 88 g/L (reference 60-80), albumin 52 g/L (35-50), urea 14.5 mmol/L (2.5-7.8), creatinine 118 µmol/L (60-110). SPEP shows all fractions raised in proportion, with no band. The most likely explanation is:
1. AHemoconcentration from fluid loss
2. BAn acute phase response to infection
3. CAn early monoclonal gammopathy
4. DPolyclonal hypergammaglobulinemia
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Answer: A · Hemoconcentration from fluid loss
Loss of water concentrates every plasma protein to the same degree, so total protein and albumin rise together and the A/G ratio stays normal (52 / 36 = 1.4). Urea has risen more than creatinine (urea:creatinine ratio about 123), which fits prerenal volume depletion. The liver does not overproduce albumin, so a raised albumin almost always means hemoconcentration or a preanalytical effect such as a long tourniquet time. Repeating the tests after rehydration confirms it.
- B: An acute phase response lowers albumin and raises the alpha bands.
- C: A monoclonal protein gives a discrete band and does not raise albumin.
- D: A polyclonal rise affects the gamma band and lowers the A/G ratio.
Question 4 · Easy
In the biuret method for serum total protein, the violet color forms when:
1. AAn anionic dye binds to basic groups on albumin
2. BFolin phenol reagent is reduced by tyrosine residues
3. CCupric ions bind peptide bonds in alkaline solution
4. DNinhydrin reacts with free alpha-amino groups
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Answer: C · Cupric ions bind peptide bonds in alkaline solution
In alkaline solution, cupric ions form a violet chelate with the nitrogen atoms of peptide bonds; at least two peptide bonds are needed, so free amino acids and dipeptides do not react. The color is read at about 540 nm and depends on the number of peptide bonds, so different proteins react almost equally. This makes biuret the routine automated method for total protein. Lipemia and hemolysis add absorbance, so a sample blank helps with turbid samples.
- A: Anionic dye binding to albumin is the principle of the BCG and BCP albumin methods.
- B: Reduction of the Folin phenol reagent by tyrosine is the Lowry method, not biuret.
- D: Ninhydrin detects free amino groups and is used mainly for amino acids.
Question 5 · Hard
A patient with IgG myeloma had an M-protein of 32 g/L before treatment. After three cycles: total protein 66 g/L (6.6 g/dL), albumin 38 g/L (3.8 g/dL), and densitometry gives the M-spike as 9% of the total area. What is the current M-protein concentration?
1. A9.0 g/L
2. B5.9 g/L
3. C2.5 g/L
4. D26.1 g/L
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Answer: B · 5.9 g/L
Densitometry reports each fraction as a percentage of the total stain, so the M-protein is that percentage of total protein: 0.09 × 66 = 5.9 g/L (0.59 g/dL). This is a fall of about 82% from 32 g/L. The gating method (perpendicular drop or tangent skimming) changes the result, so the same method should be used at every visit. Small gamma-region spikes are measured less accurately than large ones.
- A: 9.0 g/L treats the percentage as if it were a concentration.
- C: 2.5 g/L multiplies the percentage by the globulin fraction (28 g/L) instead of by total protein.
- D: 26.1 g/L is the fall from baseline, not the current level.
Question 6 · Medium
In nephrotic syndrome, the alpha-2 band on SPEP often rises while albumin and gamma fall. This is mainly because alpha-2 macroglobulin:
1. AIs filtered but then reabsorbed by the renal tubules
2. BIs too large to filter, and the liver makes more of it
3. CIs an acute phase protein driven by interleukin-6
4. DIs made by plasma cells to replace lost globulins
Answer and explanation in LearnFree account
Question 7 · Medium
SPEP: albumin slightly decreased; alpha-1 and alpha-2 increased; beta and gamma normal. This pattern is most typical of:
1. ACirrhosis of the liver
2. BAcute inflammation
3. CNephrotic syndrome
4. DChronic inflammation
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Question 8 · Hard
A patient on a heparin infusion has blood drawn into a plain serum tube. SPEP shows a sharp, narrow band between the beta and gamma zones. Immunofixation with anti-IgG, -IgA, -IgM, -kappa and -lambda shows no matching band. The most appropriate next step is:
1. AAdd thrombin to the serum and repeat the SPEP
2. BRequest a 24-hour urine for Bence Jones protein
3. CReport a probable free light chain M-protein
4. DRepeat immunofixation with anti-IgD and anti-IgE
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Question 9 · Hard
A 9-year-old has edema and chronic diarrhea. Serum albumin is 18 g/L (reference 35-50) and urine protein by reagent strip is negative. SPEP shows every fraction reduced, including alpha-2 and gamma. Which condition fits best?
1. ANephrotic syndrome
2. BAcute inflammation
3. CCirrhosis of the liver
4. DProtein-losing enteropathy
Answer and explanation in LearnFree account
Question 10 · Hard
A 66-year-old man has bone pain, recurrent chest infections and creatinine 210 µmol/L (2.4 mg/dL). SPEP: albumin normal, gamma band markedly decreased, no visible band. His urine is negative for protein by reagent strip but strongly positive with sulfosalicylic acid. The most likely diagnosis is:
1. ANephrotic syndrome
2. BLight chain (Bence Jones) myeloma
3. CCommon variable immunodeficiency
4. DIgG multiple myeloma
Answer and explanation in LearnFree account
Question 11 · Easy
The alpha-2 band on serum protein electrophoresis consists mainly of:
1. ATransferrin and complement C3
2. BAlpha-2 macroglobulin and haptoglobin
3. CAlpha-1 antitrypsin and orosomucoid
4. DImmunoglobulins G, A and M
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Question 12 · Medium
In chronic intravascular hemolysis, for example from a mechanical heart valve, which SPEP fraction is most likely to be reduced?
1. AGamma, as immunoglobulins break down
2. BAlpha-1, as alpha-1 antitrypsin is lost
3. CBeta, as transferrin is consumed
4. DAlpha-2, as haptoglobin is consumed
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Question 13 · Easy
Edema develops when serum albumin falls very low, because albumin normally supplies most of the plasma's:
1. AViscosity and resistance to flow
2. BOsmolality from small dissolved solutes
3. COncotic (colloid osmotic) pressure
4. DAcid-base buffering capacity
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Question 14 · Medium
Monoclonal proteins of which class most often migrate in the beta region, where transferrin or C3 can hide them?
1. AIgA
2. BIgG
3. CIgE
4. DIgD
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Question 15 · Medium
A 32-year-old woman with heavy menstrual bleeding has an SPEP in which only the beta-1 band is raised. Which protein most likely accounts for this?
1. AComplement C3
2. BHaptoglobin
3. CLow-density lipoprotein
4. DTransferrin
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Question 16 · Hard
A septic ICU patient with normal kidney function has serum albumin 29 g/L (2.9 g/dL) by bromocresol green (BCG) and 22 g/L (2.2 g/dL) by bromocresol purple (BCP) on the same sample. Which result is closer to the true albumin, and why?
1. ANeither; dye methods fail below 30 g/L
2. BBCP; BCG also binds acute phase alpha-globulins
3. CBCG; BCP is lowered by uremic toxins
4. DBCG; BCP is lowered by a high CRP
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Question 17 · Medium
Total protein is 68 g/L (6.8 g/dL) and albumin is 26 g/L (2.6 g/dL); the reference A/G ratio is 1.1-2.2. What is the A/G ratio, and how does it compare?
1. A0.38 (low)
2. B2.62 (high)
3. C0.62 (low)
4. D1.62 (within range)
Answer and explanation in LearnFree account
Question 18 · Medium
A broad, smooth rise across the whole gamma zone of an SPEP, with no sharp band, indicates:
1. AFree light chains in the serum
2. BA monoclonal immunoglobulin (M-protein)
3. CFibrinogen from an incompletely clotted sample
4. DA polyclonal rise in immunoglobulins
Answer and explanation in LearnFree account
Question 19 · Hard
A 41-year-old woman has fatigue and a mildly raised ALT. Total protein 94 g/L (9.4 g/dL), albumin 33 g/L (3.3 g/dL). SPEP shows a broad, diffuse increase across the gamma zone with no discrete band. Taking the reference A/G ratio as 1.1-2.2, which interpretation fits best?
1. AA/G 0.54; monoclonal gammopathy
2. BA/G 1.85; within the reference range
3. CA/G 0.35; hemoconcentration
4. DA/G 0.54; polyclonal gammopathy
Answer and explanation in LearnFree account
Question 20 · Hard
A 66-year-old woman has back pain and anemia. Her serum total protein is 98 g/L (9.8 g/dL), and her SPEP scan is shown with each fraction as a percentage of total protein. The reference A/G ratio is 1.1-2.2. What is her albumin/globulin (A/G) ratio?
Figure: MedExams
1. A0.97
2. B0.38
3. C0.61
4. D1.63
Answer and explanation in LearnFree account
Question 21 · Medium
The densitometer scan of this patient's serum proteins best fits:
Figure: MedExams
1. ANephrotic syndrome
2. BMultiple myeloma
3. CCirrhosis of the liver
4. DAcute inflammation
Answer and explanation in LearnFree account
Question 22 · Easy
Refer to the serum protein electrophoresis scan shown. The abnormal pattern is most likely caused by deficiency of:
Figure: MedExams
1. AHaptoglobin
2. BComplement C3
3. CAlpha-1 antitrypsin
4. DAlpha-2 macroglobulin
Answer and explanation in LearnFree account
Question 23 · Medium
Which monoclonal proteins does the serum immunofixation shown contain?
Figure: MedExams
1. AIgG kappa and free lambda chains
2. BIgG kappa and IgA lambda
3. CIgG lambda and IgA kappa
4. DIgA lambda and free kappa chains
Answer and explanation in LearnFree account

Plasma proteins and protein electrophoresis

In the biuret method for serum total protein, the violet color forms when:

A patient with IgG myeloma had an M-protein of 32 g/L before treatment. After three cycles: total protein 66 g/L (6.6 g/dL), albumin 38 g/L (3.8 g/dL), and densitometry gives the M-spike as 9% of the total area. What is the current M-protein concentration?

In nephrotic syndrome, the alpha-2 band on SPEP often rises while albumin and gamma fall. This is mainly because alpha-2 macroglobulin:

SPEP: albumin slightly decreased; alpha-1 and alpha-2 increased; beta and gamma normal. This pattern is most typical of:

A patient on a heparin infusion has blood drawn into a plain serum tube. SPEP shows a sharp, narrow band between the beta and gamma zones. Immunofixation with anti-IgG, -IgA, -IgM, -kappa and -lambda shows no matching band. The most appropriate next step is:

A 9-year-old has edema and chronic diarrhea. Serum albumin is 18 g/L (reference 35-50) and urine protein by reagent strip is negative. SPEP shows every fraction reduced, including alpha-2 and gamma. Which condition fits best?

A 66-year-old man has bone pain, recurrent chest infections and creatinine 210 µmol/L (2.4 mg/dL). SPEP: albumin normal, gamma band markedly decreased, no visible band. His urine is negative for protein by reagent strip but strongly positive with sulfosalicylic acid. The most likely diagnosis is:

The alpha-2 band on serum protein electrophoresis consists mainly of:

In chronic intravascular hemolysis, for example from a mechanical heart valve, which SPEP fraction is most likely to be reduced?

Edema develops when serum albumin falls very low, because albumin normally supplies most of the plasma's:

Monoclonal proteins of which class most often migrate in the beta region, where transferrin or C3 can hide them?

A 32-year-old woman with heavy menstrual bleeding has an SPEP in which only the beta-1 band is raised. Which protein most likely accounts for this?

A septic ICU patient with normal kidney function has serum albumin 29 g/L (2.9 g/dL) by bromocresol green (BCG) and 22 g/L (2.2 g/dL) by bromocresol purple (BCP) on the same sample. Which result is closer to the true albumin, and why?

Total protein is 68 g/L (6.8 g/dL) and albumin is 26 g/L (2.6 g/dL); the reference A/G ratio is 1.1-2.2. What is the A/G ratio, and how does it compare?

A broad, smooth rise across the whole gamma zone of an SPEP, with no sharp band, indicates:

A 41-year-old woman has fatigue and a mildly raised ALT. Total protein 94 g/L (9.4 g/dL), albumin 33 g/L (3.3 g/dL). SPEP shows a broad, diffuse increase across the gamma zone with no discrete band. Taking the reference A/G ratio as 1.1-2.2, which interpretation fits best?

A 66-year-old woman has back pain and anemia. Her serum total protein is 98 g/L (9.8 g/dL), and her SPEP scan is shown with each fraction as a percentage of total protein. The reference A/G ratio is 1.1-2.2. What is her albumin/globulin (A/G) ratio?

The densitometer scan of this patient's serum proteins best fits:

Refer to the serum protein electrophoresis scan shown. The abnormal pattern is most likely caused by deficiency of:

Which monoclonal proteins does the serum immunofixation shown contain?