From Renee Nutting: Is a PTT of >180 seconds always the result of heparin contamination or would such a result ever be medically desirable for a patient?
Hello, Renee, and thank you for your question. A partial thromboplastin time (PTT) of >180 seconds, or one at the limit of instrument measurement, is likely an indication of a high plasma concentration of standard unfractionated heparin (UFH), either an overdose or a UFH level for a patient just coming out of coronary artery bypass graft surgery. It could also be caused by an overdose of one of the new oral anticoagulants, dabigatran, rivaroxaban, or apixaban, or could indicate a clotted specimen in which most of the factors have been consumed. In all cases, an extremely prolonged PTT indicates an adverse event.