Analytical and clinical utility of a photometric assay for blood coagulation factor XIII

A new photometric assay for factor XIII was evaluated for its analytical performance and clinical usefulness. The test showed good performance characteristics: intra-assay coefficients of variation between 0.83 and 2.68%, inter-assay coefficients of variation from 3.4 to 4.5%. The test can be conducted rapidly on an automated analyser such as the Cobas Bio. The reference values (mean +/- 2 SD) ranged from 67 to 147% and there was no gender difference. The comparability of the photometric test with a clot lysis factor XIII test showed an acceptable coefficient of correlation r = 0.87 (p < 0.0001). The diagnostic conformity of both tests was 76.7%. Factor XIII concentrations were assessed in seven patient groups. In liver cirrhosis, M. Crohn and during pregnancy noticeable percentages of lowered values were found: i.e. 18.2%, 11.8% and 10.0% respectively. Elevated values were seen in hypertensive patients (16%) and in the small group of patients with carcinoma of the ovarium (22.2%). These results show that the incidence of acquired factor XIII deficiencies is relative low. The clinical meaning of reduced or enhanced factor XIII needs to be clarified by more extensive patient studies.