USE OF THROMBIN INHIBITORS EX-VIVO ALLOWS CRITICAL CARE CLINICAL-CHEMISTRY AND HEMATOLOGY TESTING ON COMMON SPECIMENS

Objective: To evaluate the suitability of the thrombin inhibitors PPAC K (D-phenylalanyl-L-prolyl-L-arginine chloromethylketone) or Argatroba n for anticoagulation of blood prior to critical care testing of whole blood or plasma. Design end Methods: Initially we evaluated the effec t of PPACK (0-200 mu M) or Argatroban (0-590 mu M) on serum glucose, u rea, creatinine, calcium and electrolyte tests on two chemistry analyz ers (Hitachi 717 and Ektachem 700XR). subsequently plasma and serum fr om whole blood samples containing either heparin 15,000 IU/L or PPACK 75 mu M or Argatroban 245 mu M or no anticoagulant were tested and com pared. We analysed and compared whole blood containing either PPACK 75 mu M or Argatroban 245 mu M or ethylenediaminetetraacetic acid (EDTA) using a Coulter STK-R(R) hematology analyzer at intervals for 90 minu tes. Results: The measurement of electrolytes, urea, creatinine, calci um or glucose was unaffected by either Argatroban or PPACK in either s erum or anticoagulant-specific plasmas (p > 0.05). For specimens from individual donors, serum potassium was higher than plasma potassium, i rrespective of anticoagulant used. Clinically equivalent complete bloo d counts were achieved for 60 minutes using EDTA-whole blood, or whole blood containing 245 mu M Argatroban or 75 mu M PPACK. However automa ted differential white cell counting was not reliable with either form of thrombin inhibitor-whole blood. Argatroban-anticoagulated blood de monstrated concentration and time dependent changes in platelet counts , whereas platelet counts were stable in blood containing 75 mu M PPAC K for up to 90 minutes. Conclusion: Specimens of blood anticoagulated with either 75 CIM PPACK or 245 mu M Argatroban can be used for either critical care chemistry or hematology testing.