[Reference values for the blood coagulation tests in Mexico: usefulness of the pooled plasma from blood donors]. / Valores de referencia para las pruebas de coagulación en México: utilidad de la mezcla de plasmas de donadores de sangre.

INTRODUCTION: The blood coagulation system maintains the blood in a liquid state and bleeding and thrombosis are the manifestations of its malfunction. Blood coagulation laboratory evaluates the physiology of this system. OBJECTIVE: To establish both, the reference values for several tests performed at the blood coagulation laboratory as well as the utility of the pooled plasma to perform these assays. MATERIAL AND: METHODS: In this descriptive, cross-sectional, randomized study, we collected plasma from Mexican Mestizos. Each pooled plasma was prepared with the plasma from at least 20 blood donors. We performed screening and special tests and the Levey-Jennings graphs were built and interpreted after each pass. Results of the tests were analyzed and their distribution was established using the Kolmogorov-Smirnov test. To establish the reference values we used 95% confidence intervals. RESULTS: We collected 72 pooled plasmas. The distribution for PT, APTT, and TT tests was abnormal. Although the PT test showed a bimodal distribution it was normal for factor VII. The reference values for the hemostatic, anticoagulant, and fibrinolytic factors were different from those suggested by the manufacturers. CONCLUSION: We established the reference values for the blood coagulation tests in the adult Mexican population. We have shown that the pooled plasma must be used for the screening tests. We suggest that each clinical laboratory should establish its own reference values (at least for the screening tests). To reach this objective, we encourage the use of the pooled plasma.