• Leopoldo Mariné, Gonzalo Sánchez, José Francisco Vargas, Pamela Zúñiga, Andrés Aizman, Renato Mertens, Michel Bergoeing, and Blanca Muñoz.
• Rev Med Chil. 2014 Nov 1;142(11):1392-7.

BackgroundThe therapeutic range (TR) of activated partial thromboplastin time (aPTT) for unfractionated heparin (UFH) dosing was established in the 1970 decade. Since then aPTT determination has changed. Current TR may be sub or supra-therapeutic depending on the reagents of the test, and therefore, responsible for complications of therapy.AimTo establish the TR for UFH dosing in our institution using antifactor Xa analysis as reference standard.Material And MethodsAfter obtaining an informed consent, 43 blood samples were obtained for aPTT determination and antifactor Xa assay in 23 patients treated with intravenous UFH. Samples were processed at Emergency and Hemostasis Labs. We excluded patients receiving other anticoagulants, with thrombophilia, pregnancy or liver disease.ResultsMean aPTT values in the Hemostasis and Emergency labs ​​were 57.1 ± 18.9 and 56.6 ± 18.3 seconds, respectively (p = 0.77). The squared correlation coefficients between aPTT and antifactor Xa at hemostasis and emergency labs were R2 0.5 and 0.45 respectively, p < 0.001. Using a linear regression analysis, therapeutic aPTT range values ​​in our laboratory were established between 50 and 80 seconds, corresponding to antifactor Xa values of 0.3 to 0.7 IU/mL.ConclusionsAccording to current recommendations, validation of aPTT determination with reference techniques should be done in every institution.

16 keywords...

hide…