Plasma antithrombin-III (AT-III) levels in 18 patients on maintenance haemodialysis were studied. AT-III was measured functionally and immunologically before and after dialysis. Simultaneous counts of platelets were made. Prior to dialysis the average AT-III levels and platelet counts were found to be within the lower part of the normal range. On paired analysis the dialysis was seen to induce small, but significant decreases in AT-III levels and platelet counts. A positive linear correlation was found between levels of functionally and immunologically determined AT-III. Replacement of the intravenous application of heparin with an administration of low-dose, subcutaneous heparin is suggested.

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