Collaborative study for the calibration of Ph. Eur. Heparin Sodium Biological Reference Preparation batch 4

An international collaborative study was organised under the aegis of the Biological Standardisation Programme (BSP) of the Council of Europe and the European Union to calibrate a replacement batch for the European Pharmacopoeia (Ph. Eur.) Heparin sodium Biological Reference Preparation (BRP). Seventeen laboratories contributed data to value assign a candidate batch (cBRP4) in International Units (IU) against the WHO 6th International Standard for Unfractionated Heparin using chromogenic and sheep plasma clotting assays according to Ph. Eur. texts 2.7.5. on unfractionated heparin and 0878 on human antithrombin III. The continuity of consecutive batches of BRP was evaluated by including BRP3 in the set of test samples. The central analysis of the study data showed good precision and reproducibility of both chromo-genic and clotting assays among laboratories. Based on the study data, the Ph. Eur. Commission adopted cBRP4 as Ph. Eur. Heparin sodium BRP4 with assigned activities of 985 IU/mL for anti-IIa assays, 995 IU/mL for anti-Xa assays and 1035 IU/mL for sheep clotting assays.