Analytical and clinical performance of two cardiac troponin I immunoassays.

Cardiac troponin I assays for Axsym (Abbott Diagnostics, Abbott Park, IL, USA) and Immuno 1 (Bayer Corporation, Tarrytown, NY, USA) analysers were evaluated. Heparin plasma or serum could be used for both assays. Samples were stable for 24 h at ambient temperature, 3 days at 4-8 degrees C and 3 months at -20 degrees C. After 10 months' storage at -80 degrees C, the recoveries were well above 100% by both assays. Total coefficients of variation for Axsym assay were 9.0%, 5.8% and 5.3% at concentrations of 2.6 microg/l, 9.83 microg/l and 34.3 microg/l respectively; for Immuno 1 these were 4.4 %, 1.6% and 1.8% at 2.3 microg/l, 6.27 microg/l and 44.35 microg/l respectively. It was > or =20% at concentration of < or =0.5 microg/l for Axysm assay and < or =0.15 microg/l for Immuno 1 assay. Recoveries were < or =90% at < or =0.22 microg/l on Axsym and at < or =1.47 microg/l on Immuno 1. Neither method showed significant interference with haemoglobin, bilirubin, triglycerides or rheumatoid factor. Correlation between the two methods was excellent (r = 0.997, Y (Axsym) = 4.2X (Immuno 1) +3.2). The highest concentrations detected in 50 healthy subjects were 0.3 microg/l and 0.1 microg/l by Axsym and Immuno 1 methods, respectively. Twelve out of 43 renal failure patients had troponin I 0.13-0.9 microg/l using Axsym method and 4 had levels of 0.07-0.13 microg/l using Immuno 1. In muscle trauma patients, troponin I was undetectable.

Serum tissue polypeptide antigen (TPA) as tumor marker for bladder cancer.

Tissue polypeptide antigen is a differentiation and proliferation marker of non-squamous epithelium and derived neoplasms. No reliable tumor markers are available for bladder cancer. The value of tissue polypeptide antigen was therefore prospectively investigated. The serum tissue polypeptide antigen samples were obtained from 144 newly diagnosed transitional cell carcinoma patients and from 92 patients that were followed after treatment. The normal cut off value was defined at 95 units per liter. Nearly all TaT1 patients had normal TPA values, and 80% of the muscle invasive cancers had normal TPA levels. In those patients where TPA was elevated before treatment its monitoring proved to be a reliable predictor of tumor progression. Tissue polypeptide antigen is a useful marker not for the early detection of bladder cancer but for the monitoring of the efficacy of a treatment.

Clinical significance of squamous cell carcinoma antigen in cancer of the human uterine cervix. Comparison with CEA and CA-125.

Serum squamous cell carcinoma antigen (SCCa) concentrations were determined by a radioimmunoassay kit before and during the treatment of 50 patients with cervical carcinoma: 44 with squamous cell carcinoma (SCC) and 6 with adenocarcinoma. The positivity rate of SCCa was 50% (52% for SCC and 33% for adenocarcinoma). The sensitivity of SCCa for SCC was twice as high as that of CEA and CA-125. Low serum concentrations were observed in early-stage carcinoma, indicating that SCCa is not useful for diagnosis. In advanced cases, serum levels were directly and significantly correlated with the stage of the disease.