A in-patient has a prolonged APTT - that is all that you know-
How do you cost effectively work up this patient- so as to maximize the information you give to the clinician and minimze the costs to the laboratory?
Your first line of testing on an inpatient is to make sure the sample is not contaminated with heparin. The best test for residual heparin is a thrombin time. If this is normal, you can proceed with your next line of testing- which would be to look for an inhibitor or a factor deficiency. If the test is prolonged, and the fibrinogen is normal, you most likely have heparin in the sample. You can request another sample, or you can treat the plasma with Hepzyme (SIEMENS) which will neutralize the heparin and you can now test the sample.
You can then go on to do your mixing study, and based on that result work up either an inhibitor or a factor deficiency.
Testing in this manner is the most cost effective way to approach this prolonged APTT.
