1.
Comparison of Electrophoretic Methods
in Multiple Myeloma Patients
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2.
Terms and Definitions
• Capillary electrophoresis (CE): a liquid-based protein separation
system, having advantage of quick and automated.
• Subtraction immunotyping electrophoresis (IT): seperates serum
proteins using antisera for each of the heavy and light chains.
• Agarose gel electrophoresis (AGE): One of the most commonly used
clinical method for protein electrophoresis.
• Immunofixation electrophoresis (IFE): is used to confirm the
presence of monoclonal bands and to identify the type of paraprotein
Am J Clin Pathol. 2008;129:451-458.

3.
A Clinical Question
• Is the capillary electrophoresis appropriate methods
as good as gel electrophoresis
to detect monoclonal protein in the serum or urine
in following-up multiple myeloma patients?
▶so that, we can reason the observed phenomenon in the 2 cases.
• Articles reviewed includes
• McCudden et al. Am J Clin Pathol. 2008;129:451-458.
• Cho and Jeon et al. Ann Clin Lab Sci. 2013;43:285-288.
• Cho et al. Clin Lab. 2013;59(3-4):445-448. (abstract only)

4.
McCudden 2008
• CE is more sensitive than AGE
• Avoidance of application artifacts
• Superior detection of β-region migrating monoclonal proteins
• CE is less specific than AGE
• Direct photometric detection of proteins during electrophoresis, resulting in
minor abnormalities in the electrophoretogram not typically observed in
those derived from scanning densitometry.

5.
McCudden 2008
• The IT method was less sensitive than AGE or CE for the detection of
monoclonal immunoglobulins.
• In particular, specimens contained monoclonal immunoglobulins at low
concentrations (<0.3 g/dL),
• Monoclonal free light chains,
• multiple (oligoclonal) bands
were often incorrectly typed by interpreters using IT.

6.
Cho and Jeon 2013
• Small peaks in capillary electrophoresis could be important findings as
precursors to large and clear monoclonal peaks in the future.
• K/L ratio by the sFLC assay is highly useful as an auxiliary method for
electrophoresis, because where the K/L skewing results significantly
improved monoclonality detection.
Ann Clin Lab Sci. 2013;43:285-288.

7.
Free Light Chain (FLC) Assay
• A sensitive antibody-based system that can detect
low concentrations of monoclonal free light chains.
• FLC kappa – 22.5 kDa, monomer
FLC lambda – 45 kDa, dimer
FLC kappa to lambda in serum = 1:1.6
• Free serum kappa light chains – 3.3 to 19.4 mg/L
Free serum lambda light chains – 5.7 to 26.3 mg/L
Kappa to lambda ratio – 0.26 to 1.65
Lancet. 2003;8;361(9356):489-91.

8.
Conclusion
• Subtle peak in UPEP by capillary method in the case 1 (M/72), which
is not visible in GE, might be a false positive results in CE.
• However, since small peaks in the CE could possibly predict future
huge increase in M-protein, the interpretation better to be conducted
with FLC assay results.
• The case 2 (F/66), which did not show peak in subtraction
immunotyping, but did in gel immunofixation, might be explained by
detection limit of the capillary electrophoresis method.

9.
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감사합니다.