I received this note from Stephen Duff, Co-CEO of Precision BioLogic about my recent “Top Ten” post:
I noted with interest your Top Ten summary over the years and was puzzled to see “PTT Heparin Therapeutic Range” 2006 with a check mark beside it for “Resolved”. I think many labs still struggle with getting a sufficient number of samples to perform the Brill-Edwards exercise and many do not have an anti-Xa up and running. Any insights?
Hi, Steve, and thanks for reviewing my Top Ten Problems Through the Agessummary. I may have had a brain cramp when I typed that check mark in the “Resolved” column for “PTT Heparin Therapeutic Range,” but my thinking at the moment was that when you add up those who have changed over to low molecular weight heparin and the synthetic pentasaccharide fondaparinux, plus those who have gone from the PTT to the chromogenic (or clot-based) anti-Xa heparin assay, and throw in the advent of the new oral anticoagulants rivaroxaban, apixiban, and dabigatran, surely the need for the Brill-Edwards curve has gone on the endangered, if not the extinct list. However, I went back to our December 20, 2008 Quick Question, “Unfractionated Heparin Management,” and realized that many of us were still spiking specimens to make a heparin curve only three years ago, and many more were using ex vivo calibration. I’d been concluding that most of those 500 daily PTTs we perform in our laboratory are just holdovers from when physicians automatically checked PT and PTT together on all patients.
So, before throwing in the sponge and taking out that offending check mark; on Monday, October 24, I will post a reprise of our 2008 Quick Question to learn how far we’ve come in monitoring heparin, and whether we can really claim the “ex vivo” calibration curve has been resolved. Geo.