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March 21, 1925


Author Affiliations

Madison, Wis.
From the Pharmacological Laboratory of the University of Wisconsin.

JAMA. 1925;84(12):890-891. doi:10.1001/jama.1925.26620380001009a

The great number of methods proposed for platelet counting indicates no universal satisfaction with any one. As a result of careful studies on the various technics suggested, we were led to adopt that introduced by Kemp, Calhoun and Harris,1 with the exception that we found another diluting fluid much more satisfactory than the one used by them. Indeed, no other diluting fluid has given us as consistently good service as the one we were led to formulate.

The anticoagulant used in most diluting fluids for platelet counting is sodium citrate. In order to obtain an isotonic solution with this salt, such quantities must be used that the specific gravity of the fluid becomes relatively high, with the result that the platelets take a long time to settle on the counting chamber. In addition, sodium citrate does not satisfactorily prevent the platelets from clumping. It was observed long ago that