The analytical value for kinin concentration in blood depends on the antiserum used in the bradykinin radioimmunoassay.

Recently published blood kinin concentrations are subject a wide scatter, due to sampling time and technique. In our study we tested the influence of the used antibradykinin antiserum on the measured kinin concentration in blood. Blood was collected from the anticubital vein by a teflon cannula and inactivated immediately by hydrochloric acid in the syringe. Subsequent extraction was performed using diethylether, n-butanol, distilled water and Biorex-70. The blood extract containing the kinins was divided into four samples and measured by four radioimmunoassays using different antibradykinin antibodies. All four assays were performed under standard conditions and at the same time. The resulting kinin values were similar in two assays: 7.4 +/- 2.6 ng/l and 5.6 +/- 1.3 ng/l. In the two other assays, however, the measured kinin concentrations differed markedly from these values: 127.5 +/- 46.7 ng/l and 693.0 +/- 85.7 ng/l. These results indicate clearly that the antibody used in the assay can be a major factor determining the range of the recorded kinin concentration.