Development of a microparticle-enhanced nephelometric immunoassay for quantitation of human lysozyme in pleural effusion and plasma

✍ Scribed by M. Caballero; R. Ruiz; M. Márquez de Prado; M. Seco; L. Borque; J.F. Escanero

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 101 KB
• Volume: 13
• Category: Article
• ISSN: 0887-8013
• DOI: 10.1002/(sici)1098-2825(1999)13:6<301::aid-jcla9>3.0.co;2-3

✦ Synopsis

A microparticle-enhanced nephelometric immunoassay, based on polystyrene beads coated with antihuman lysozyme antibody, has been developed for lysozyme quantification in sera and pleural effusions. The standard curve extends from 0.58 mg/l to 18.75 mg/l and no antigen effect was observed. The results showed a good serial precision. The intra-assay precision (n = 20) expressed as CV was between 2.2 and 4.2 in three different concentrations. The interassay precision, with different calibration curves (n = 12) was between 6.4 and 7.1. The analytical assay showed a sufficient linearity (r > 0.999). There were no interfer-ences either with haemoglobin (up to 4 g/l), lipids (up to 0.5%, expressed as l% Lipofundina® content), or bilirubin (up to 5 mg/dl). The analytical sensitivity was lower than 0.6 mg/l. The correlation with a Micrococcus lysodeikticus turbidimetric assay showed a correlation coefficient of 0.915. We have studied 92 patients with pleural effusion. In each case, pleural fluid adenosine deaminase activity and pleural fluid to plasma lysozyme ratio were determined. The lysozyme ratio showed similar clinical sensitivity and specificity as to adenosine deaminase.