[Reference values for protein C activity in healthy adults in Mexico].

Protein C (pC) is a natural-occurring anticoagulant and its acquired or hereditary deficiency has been associated with thrombosis. For its screening, technics that appraise both its plasmatic concentration and biological activity are used. The quantitative deficiency is important, but some characteristics of pC activity (pCA) suggest an essential role of the functional deficiency. Because reference levels have not been previously described in Mexico, we report here the results of a pCA assessed by a chromogenic assay in 88 adult healthy mexican people between 15 and 69 years of age. The pCA values at the 2.5 and 97.5% percentiles in our population were 75 and 137% in normal plasma. Functional disorders of this protein have been described in the presence of normal pC quantitative levels and, therefore, there are individuals with low pC concentrations and a normal pCA without thrombosis. These data suggest that the pCA could be a more important screening test than the quantitative determination as the first step in the study of a possible deficiency state of protein C.