IMMUNOQUANTIFICATION OF LIPOPROTEIN(A) - COMPARISON OF NEPHELOMETRY WITH ELECTROIMMUNODIFFUSION

A new fully automated nephelometric immunoassay for lipoprotein(a) qua ntification in human serum was evaluated using the Behring Nephelomete r Analyzer The assay exhibited a good linearity in the concentration r ange of 110-1,770 mg/l; at higher concentrations, samples were automat ically diluted by a factor of 4. The method is simple, robust, and sho ws an excellent stability of the calibration curve over several weeks. Intra-assay and day-to-day coefficients of variation were 2% and 4.5% , respectively The method correlated well with electroimmunodiffusion (r = 0.977; n = 123; P = 0.0001). Unspecific turbidity as expressed by an elevated blank value occurred in 3% of all freshly measured sample s (n = 392). Storage of the samples for 1 week at 4-degrees-C had no s ignificant influence on the results. Frozen sera, on the other hand, c annot be assayed by this method. We believe that this assay is well su ited for use in clinical routine work. (C) 1993 Wiley-Liss, Inc.