ACLS
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Tseng, C. H.
Right arrow Articles by Liu, F. J.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Tseng, C. H.
Right arrow Articles by Liu, F. J.
Annals of Clinical & Laboratory Science 33:160-166 (2003)
© 2003 Association of Clinical Scientists

Accuracy of Serum IgM and IgA Monoclonal Protein Measurements by Densitometry

C. Howard Tseng1, Chin-Yung Chang2, Kevin S. Liu3 and Frank J. Liu2
1 Department of Pathology, Chung Shan Medical University Hospital, Taichung, Taiwan;
2 Department of Laboratory Medicine, The University of Texas M.D. Anderson Cancer Center, Houston, Texas;
3 Department of Family Medicine, Scott & White Clinics, Texas A & M University College of Medicine, Waco, Texas

Address correspondence to Frank J. Liu, M.D., 1910 Gray Birch Drive, Sugar Land, Texas 77479, USA; tel 832 724 9037; fax 281 565 9520; e-mail frankjliu_1139{at}yahoo.com. Dr. Chin-Yung Chang is now affiliated with the Department of Pathology, St. Mary’s Medical Center, Hobart, IN, USA.

We previously reported that proper dilution of sera that contain IgG monoclonal proteins (M-proteins) is necessary for accurate quantitation of serum albumin and M-protein concentrations separated by serum protein electrophoresis (SPE) using the Beckman PARAGONTM agarose electrophoresis system. We now report the significance of pre-electrophoretic serum dilution for M-protein quantitation of sera from patients with IgA and IgM monoclonal gammopathy. We measured M-proteins by SPE in 82 serum samples from 29 patients with IgA and 72 samples from 23 patients with IgM monoclonal gammopathy. The serum M-protein concentrations (mean ± SD) at 1:5, 1:10, and 1:20 dilutions (v/v) for all samples of both types were 49.7 ± 12.9, 49.1 ± 13.1, and 47.8 ± 13.0 g/L, respectively. Thirty-two (20.8%) of 154 sera showed varying degrees of increase in M-protein concentrations with serum dilutions higher than 1:5; only 8 (5.2%) showed an increase 3 SDs. By SPE, the M-protein concentration (mean ± SD) of these 8 sera at 1:5, 1:10, and 1:20 dilutions were 52.6 ± 7.8, 57.1 ± 7.2, and 57.6 ± 7.1 g/L, respectively; the albumin concentrations (mean ± SD) were 41.4 ± 4.4, 37.9 ± 3.8, and 37.1 ± 2.9 g/L, respectively. The corresponding albumin concentration (mean ± SD) was 36.8 ± 3.7 g/L, assayed by the bromcresol green dye-binding method. These 8 samples were obtained from 3 patients, 2 with IgM kappa and 1 with IgA lambda monoclonal gammopathy. On the electrophoresis membranes, the M-protein bands of these 8 samples were narrow, thin, and dense; upon scanning, they appeared taller and thinner than the corresponding albumin bands. The samples of this subset contained relatively high concentrations of M-protein and total serum protein. We conclude that a pre-electrophoretic dilution of 1:5 (v/v) is adequate for most sera with IgA or IgM M-proteins. However, 1:10 or 1:20 dilution is occasionally required for a subset of sera with IgA or IgM M-proteins that show an unusually thin, narrow, and dense M-protein band and have high total serum protein content.

Keywords: monoclonal gammopathy, IgA, IgM, M-protein, serum protein electrophoresis






HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 2003 by the Association of Clinical Scientists.