Development and validation of an automated particle-enhanced nephelometric immunoassay method for the measurement of human plasma c1q

✍ Scribed by Dr. Luis Borque; V. Olivan; F. Iguaz

• Publisher: John Wiley and Sons
• Year: 1995
• Tongue: English
• Weight: 527 KB
• Volume: 9
• Category: Article
• ISSN: 0887-8013
• DOI: 10.1002/jcla.1860090505

✦ Synopsis

We have developed a sensitive immunoassay based on latex particle agglutination for measuring C l q concentrations in human plasma. In this simple and fast particle-enhanced immunoassay, we used carboxylated latex particles (diameter 210 nm) covalently coated with F(ab')2 fragments of anti-Clq antibodies. These particles are incubated with diluted sample (400-fold) for 6 min at room temperature, with the resulting agglutination quantified by measuring the change of lightscatter produced. The assay has been automated on the Behring nephelometer analyzer with a sampling rate of 150 sampleslhr. This assay generates a standard curve in the range of 24-775 mg/L, showing intraassay and interassay precision of <8% and <lo%, respectively. Dilution linearity was validated throughout the dynamic range of the assay. There were no interferences from bilirubin, Intralipid, haemoglobin, and rheumatoid factor. Results obtained in 45 clinical samples correlated well with those obtained by a commercial radial immunodiffusion method (r = 0.936), and with those obtained by the Behring immunoprecipitation nephelometric test (r = 0.950). The mean concentration in plasma from healthy subjects was 180 mg/ L and the reference interval was from 128 to 237 mg/L. This latex nephelometric procedure is a convenient method and an interesting alternative to other immunoassays for routine measurement of human C l q .