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We report on the occurrence of monoclonal components observed in a provincial hospital in northern Italy from 1987 to 1990. The monoclonal components were detected by visual inspection of high‐resolution acetate serum electrophoreses and typed by immunofixation. The percentage of monoclonal components increases steeply with age, and reaches a plateau of 7–8% in individuals over 55 years old. Besides the high percentage of monoclonal component, the other relevant finding of this study is that ˜80% of monoclonal components are of low concentration (<5 g/l). Most of these subjects with small monoclonal component passed undetected in the previous studies on the prognostic significance of monoclonal gammapathy. These findings indicate the need for a revision of the current concepts on the biological and clinical significance of MC discovered by chance.

Serum protein electrophoresis and typing of monoclonal components (MCs) are routine but time-consuming and technically demanding assays. We evaluated capillary electrophoresis (Paragon CZETM 2000) for automation of the two assays. CZE and cellulose acetate electrophoresis gave similar data on 794 samples. Within-run and between-run CVs were &lt;2% for albumin and γ-globulins and 4–7% for α1-, α2-, and β-globulins. Bilirubin, hemoglobin, triglycerides, and fibrinogen were found not to interfere. No carryover by capillaries was detected. The detection limit for MC was &lt;0.5 g/L. MC assessment by immunosubtraction on 403 samples identified the monoclonal type in all samples with peak concentrations &gt;10 g/L; only 50% of MCs that could not be quantified by densitometric scan were typed.

No abstract

A simple immunoturbidimetric method for quantifying apolipoproteins (apo) A-I and B in serum or plasma is described. A special reagent formulation, including large amounts of suitable detergents, obviates the need for a sample blank even with grossly lipemic specimens. The assay is rapid, easily automated, and thus convenient for routine work. For both apo A-I and apo B, the assay range is about 0.2-3.5 g/L. The performance characteristics were assessed with discrete (Optimate and Olli CD) and centrifugal analyzers (Cobas Fara and IL Monarch 2000). Average analytical recovery was 101.5% for apo A-I and 99.4% for apo B. Dilution tests showed found/expected ratios of 101.2% (apo A-I) and 101.0% (apo B). Overall precision (CV) ranged from 1.4% to 3.3% for apo A-I and from 1.1% to 8.3% for apo B. Comparisons with commercially available rate nephelometry, radial immunodiffusion, and immunoturbidimetric methods gave good correlations (r greater than or equal to 0.938). Using the immunoturbidimetric method, we also established the relationships between apolipoproteins and lipids and determined the reference intervals. We conclude that the proposed method is suitable for routine use in clinical laboratories.