Unexplained Prolonged PT and PTT

From “ssusko”:

I have a question about an extremely perplexing patient. She is a 49 year old female who came in through the ED. She had a moderately decreased H&H (HGB 8.9, HCT 26.3) and a normal platelet count. However, her prothrombin time (PT) was through the roof—we could not get a reading as it was way over 250 seconds. The clot curve showed that the result was correct. Her partial thromboplastin time (PTT) was 73 seconds. Testing of a recollected sample confirmed the original results. The patient insisted that she was not on coumadin (never was) and that no one in her household was either. A coumadin level was sent out anyway and was (message terminates here).

Hello, and thank you for your question. As it was truncated, please respond with whatever additional information you can provide. I’m posting this with the hopes that one or more of our subscribers may have a suggestion. Please include a description of the complaint that compelled her to go to the ED.

My first response to results that are this prolonged is to distrust the specimen. In this case, confirmation by the duplicate specimen should remove my distrust, unless both specimens were collected above an intravenous line or allowed to clot. It is worth checking both specimens for their integrity, particularly as you mention no acute bleeding.

Assuming the specimens are valid, there may be some form of therapy that is interfering in the assay.

You are correct to next look for coumadin, even though the patient reports no coumadin. She could have had accidental coumadin exposure, but again, this would be accompanied with bleeding. A direct thrombin inhibitor such as argatroban, or the new oral DTI, dabigatran, could also be responsible.

The mild anemia may imply a chronic bleeding or hemolytic disorder resulting in iron or folate deficiency, however, the extreme PT and moderately prolonged PTT results point to a more acute situation such as liver disease or vitamin K deficiency. Again, both would be accompanied by bleeding.

These are my suggestions for the present, please follow up with the missing information, and also watch this post for suggestions from our experienced participants.