Improved sensitivity of capillary electrophoresis for detection of bisalbuminemia.
We wish to report our findings on bisalbuminemia detected by capillary electrophoresis. Bisalbuminemia is an abnormality characterized by a double band of albumin seen on electrophoresis. This anomaly can be either inherited or acquired. The inherited familial bisalbuminemia is a rare abnormality with no pathologic or therapeutic consequences, being of interest only for human genetics or anthropology (1). By contrast, the detection of an acquired and transitory bisalbuminemia may point to an overdose of antibiotics or the presence of ascites or a pancreatic pseudocyst (2, 3).
Since the introduction of the Paragon 2000[TM] capillary zone electrophoresis (CZE) system (Beckman Instruments) in our laboratory, we have noted an increased frequency of identified cases of bisalbuminemia. The electrophoretic separation was performed according to the manufacturer's instructions, in borate buffer (pH 10) at 9000 V with online detection at 214 nm. We have analyzed 6500 samples by CZE in the last year and detected 8 bisalbuminemias (Fig. 1A). This frequency of bisalbuminemia is high: in a similar number of analyses performed annually by classical agarose gel electrophoresis, we detected only one case of bisalbuminemia in the last 4 years.
We were able to reinvestigate five of these eight patients. Agarose gel electrophoresis performed on the same samples from these five patients did not detect any abnormality of the albumin fraction (Fig. 1B). The morphology of the albumin peak in the eight cases detected with CZE and in the only case that could be detected by both methods was similar. These patients did not take antibiotics or present any pancreatic disease (suggesting an absence of pancreatic pseudocysts). Study of two of these patients 3 month later gave the same result: a bicuspid electrophoretic pattern in the albumin fraction detected by capillary electrophoresis that was not seen with agarose electrophoresis. The albumin composition of this serum component has been confirmed by immunofixation of the sample with anti-albumin antisera (data not shown). Moreover, no discordances were found between the nephelometric quantification of albumin with a Behring BN100 (Behringwerke) instrument (46 g/L) and the albumin concentration determined by capillary electrophoresis (43 g/L). Immunofixation with anti-IgG, -IgA, and -IgM [kappa] and [lambda] light chains did not show the presence of monoclonal components. Reduction with mercaptoethanol (1:2 dilution), which dissociates complexes but does not dissociate albumin dimers, excluded the possible formation of complexes with [[alpha].sub.1]-antitrypsin. Interferences by radio-opaque agents or medications, which could lead to the appearance in the CZE electropherograms of abnormal peaks, were discarded as explanations because they are visible in the [[alpha].sub.2] -globulin fraction or (3 region and do not show a bicuspid electrophoretic pattern (4).
[FIGURE 1 OMITTED]
The demonstration of a double albumin line on protein electrophoresis depends on the method used for separating blood proteins. Agarose gel electrophoresis has good separation of the [beta] and [gamma] globulins, but CZE shows improved separation of the albumin, [[alpha].sub.1], and [[alpha].sub.2] fractions (5). Meiers et al. (6) reported that the method of choice is cellulose-acetate foil electrophoresis because of its high sensitivity, but this method lacks specificity. Our results indicate that with the new capillary electrophoresis, more cases of this rare and interesting electrophoretic abnormality may be detected. However, further research is needed to confirm the clinical importance of the additional cases of bisalbuminemia detected by CZE.
We thank M. Filot, F. Egger, and the technical personnel of the Protein Diagnosis Laboratory, Department of Clinical Chemistry, University Hospital, Berne, Switzerland for their assistance.
(1.) Ott H, Feinauer B. Bisalbuminaemie in Stuttgart. Dtsch Med Wochenschr 1973;98: 1941-6.
(2.) Rousseaux J, Debeaumont D, Scharfman A, Pommelet P, Dautrevaux M, Biserte G. Bisalbuminemies au cours des pancreatites: modifications structurales de la serumalbumine humaine par les enzymes proteolytiques du pancreas. Clin Chim Acta 1976;71:35-46.
(3.) Kobayashi S, Okamura N, Kamoi K, Sugita 0. Bisalbumin (fast, slow type) induced by human pancreatic juice. Ann Clin Biochem 1995;32: 63-7.
(4.) Thormann W, Wey AB, Lurie IS, Gerber H, Byland C, Malik N, et al. Capillary electrophoresis in clinical and forensic analysis: recent advances and breakthrough to routine applications. Electrophoresis 1999;20:3203-36.
(5.) Keren DF. Capillary zone electrophoresis in the evaluation of serum protein abnormalities. Am J Clin Pathol 1998;110:248-52.
(6.) Meiers HG, Strassburger D, Stephan W, Just I, Jantzen W. Nachweis von Alloalbuminaemien (Bisalbuminaemien). Dtsch Med Wochenschr 1973;98:1941-6.
Department of Clinical Chemistry
University Hospital, Inselspital
* Author for correspondence. Fax 41-31632-4862; e-mail email@example.com.
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|Author:||Jaeggi-Groisman, Silvia E.; Byland, Christa; Gerber, Hans|
|Article Type:||Letter to the editor|
|Date:||Jun 1, 2000|
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