The determination of alpha 1-microglobulin by means of an automated latex immunoassay.
Polystyrene (latex) particles coated with human anti-alpha 1 microglobulin antibodies are used in an automated "kinetic" assay for alpha 1-microglobulin in urine. For values below 12 mg/l, there was no significant difference between two kinds of standard, but above 12 mg/l the results depend on the origin of the alpha 1-microglobulin standard. Correlation between values obtained with both standards was good (r2 = 0.968). The method has a between-run imprecision (CV) of 11-16%. Comparison with two commercial enzyme immunoassays gave a bias of -10% to +40%, while two nephelometric methods differed by 0% to 23%, possibly because the standards used in these methods were of different origin. These results indicate the necessity of standardization of the determination of alpha 1-microglobulin. The detection limit of our method was 0.8 mg/l, enabling the application of the method for epidemiological investigations.