Microparticle immunoenzymatic assay for detection of prostate specific antigen: characterization of the technique and comparative analysis with a monoclonal immunoradiometric assay

• Published in: Military medicine Vol. 160; no. 8; p. 416
• Main Authors: Sánchez de la Muela, P, Povo Castilla, J, Bobillo de Lamo, M, Rosales, F, Pérez-Piqueras, J L
• Format: Journal Article
• Language: English
• Published: England 01.08.1995
• Subjects: Adolescent; Adult; Aged; Aged, 80 and over; Antibodies, Monoclonal; Humans; Immunoenzyme Techniques; Immunoradiometric Assay - methods; Male; Middle Aged; Prospective Studies; Prostate-Specific Antigen - blood; Reproducibility of Results; Sensitivity and Specificity; Ureteral Obstruction - blood
• ISSN: 0026-4075
• DOI: 10.1093/milmed/160.8.416

Microparticle immunoenzymatic assay (MEIA) is a new, ultrasensitive technique recently introduced for detection of prostatic specific antigen (PSA). It is easily performed, totally automated, and cheaper and faster than radioimmunometric techniques. In this study, the levels of PSA in 194 males with urologic problems and healthy males, recorded by microparticle monoclonal ultrasensitive enzymoimmunoassay (MEIA) and immunoradiometric assay (IRMA), are comparatively evaluated. Variables recorded were age of patient, size and weight of the prostate, and PSA levels analyzed by the MEIA (MEIA-PSA) and IRMA (ELSA-PSA) techniques. Different determinations of PSA were performed in order to calculate the intra- and interassay variation coefficient for the MEIA-PSA assay. Means of prostatic length, width, and depth, recorded by ultrasonography, were 28.3, 35.8, and 31.4 mm, respectively, with a mean prostatic size of 19 ml and a mean prostatic weight of 23.9 g. Mean IRMA-PSA was 4.53 ng/ml and mean MEIA-PSA was 2.04 ng/ml. The difference between them was 2.49, and the ratio IRMA-PSA:MEIA-PSA was 3.17. Interassay and intraassay variation coefficients for MEIA-PSA were 6.58 and 9.96%, respectively. MEIA-PSA values correlated linearly with the age of the patients (r = 0.65, p = 0.0001), size of the prostate (r = 0.71, p = 0.0001), weight of the prostate (r = 0.71, p = 0.0001), and the value of IRMA-PSA (r = 0.80, p = 0.0001). Paired t tests showed that the values of PSA measured by MEIA and IRMA are statistically different (p = 0.0001), with independence of the level of PSA considered.