A solid phase immunoassay for aldosterone using enhanced chemiluminescent detection has been developed. Monoclonal antibodies against aldosterone were used for the immune reaction and compared with polyclonal antibodies. Uniform Protein A coated polystyrene tubes were used as solid phase for the monoclonal antibody and second (anti-rabbit) antibody coated tubes for the polyclonal antibody. Horseradish peroxidase was covalently linked to aldosterone as enzyme label. Optimum conditions were established for the generation and measurement of the luminescent reactions using luminol, p-iodophenol as enhancer and hydrogen peroxide. The advantages of this assay are the high sensitivity with a detection limit of 100 fg/tube, the prolonged luminescence signal with a simplification of the measurement (simpler detectors, external start pipetting) and the short measure time with the possibility of repeated measurement. The coefficients of variation were 4.2%-7.3% in the concentration range 140-1180 pmol/l. The assay showed a significant correlation (r = 0.91) with the ELISA. The aldosterone concentrations in plasma and saliva of patients with Conn's syndrome were significantly increased, and in patients with Addison's disease were found near the detection limit.

Aldosterone↗

PubMedDate not supplied

Multicenter evaluation of the Elecsys CA 125 II assay.

The technical performance and clinical usefulness of the newly developed Elecsys CA 125 II assay (Boehringer Mannheim) was evaluated in a multicenter study. Imprecision studies were carried out using control sera and human pool sera with CA 125 concentrations from 11 to 1026 U/ml. Within-run CVs between 0.7 to 4.8% (median 1.7%) and between-day CVs between 2.4 to 10.9% (median 5.7%) were found. Method comparison studies with Enzymun-Test CA 125 II carried out in four laboratories yielded slopes between 0.94 to 1.07 and intercepts < 3 U/ml. A good comparability of the Elecsys CA 125 II assay was also found with one MEIA and the Centocor" IRMA. For a second MEIA and a second IRMA the slopes were 1.23 and 1.42, and the corresponding correlation coefficients were 0.987 and 0.977, respectively. The Elecys CA 125 II concentrations are clearly related to the tumor stage of ovarian carcinoma patients. The maximum of diagnostic efficiency of ovarian carcinoma patients compared with patients of benign gynecological diseases is reached at 150 U/ml with a specificity of 93% and a sensitivity of 69%. Follow-up studies of ovarian carcinoma patients reflect the status of the disease and the effect of various therapeutic applications. The technical and clinical evaluation of the Elecsys CA 125 II assay show a superior analytical performance with a broad measuring range up to 5000 U/ml and a short measuring time of 18 minutes.

Biomarkers, Tumor↗