Here is one of our April 22, 2018 Medical Laboratory Professionals Week case studies for your response. Watch for more “Lab Week” case studies in the weeks ahead!
I (George) have corresponded with a gentleman since 2009; we’ve developed an electronic friendship, though we’ve never met F2F.
“John” first contacted me in 2009, a year after Precision BioLogic and I launched Fritsma Factor. John is a professional man who claims to be overweight but who plays ice hockey for recreation. A puck hit him in the calf in 2009, and when the pain and swelling persisted, he saw his primary care physician who ordered an ultrasound, which indicated deep vein thrombosis. John’s doctor started him on a round of Coumadin therapy and monthly PT/INRs. His treatment course was uneventful, and after the Coumadin was discontinued he had a thrombophilia workup that returned normal results except for homocysteinemia. John took over the counter folate, vitamin B6, and vitamin B12 plus a baby aspirin but had discontinued all four sometime along the way. He continues to play hockey.
On February 10, 2018, John experienced new pain in the location of the old clot, this time not related to his physical activities—that is, no identifiable trigger. His primary had retired, so he saw an ER doctor, who ordered a new ultrasound. The radiologist read the old DVT location as having two consolidated clots and one new one. Neither doctor had access to the 2009 image, only a written summary. On the basis of the new finding, John was prescribed Xarelto (rivaroxaban), which he is continuing, and which he reports causes more profuse and prolonged bleeds subsequent to shaving nicks than did the Coumadin. He has been offered no laboratory assay. John is retired, but when he was working he traveled often and never had a travel-associated DVT.
Here are John’s questions, which I paraphrase…
- · How accurate is his new diagnosis?
- How long will he be required to stay on Xarelto?
- · What are the Xarelto bleeding characteristics?
- · How is Xarelto best measured, and what is the value of assaying Xarelto?
- · Should he have a new set of thrombosis risk tests? Which should be repeated?
- · Could the new episode indicate onset of a new risk factor such as lupus anticoagulant or cancer?