Choice of Platelet Anticoagulants

Excerpt

To the editor: I read the article by Dr. Kelton (1) with interest and found one statement questionable. Kelton wrote that "Only edetic-acid-anticoagulated capillary tubes should be used (not capillary tubes anticoagulated with heparin, because heparin causes platelet clumping and can result in a spuriously low platelet count)." In-vitro clumping of platelets resulting in a spuriously low count is one of the mechanisms of pseudothrombocytopenia; however, review of literature seems to implicate the presence of edetic acid in such a phenomenon (2). In this study platelet agglutination was seen in presence of edetic acid as well as penta-acetic acid and