Anticoagulant Therapy

R-T Estimation of the INR

Despite the onslaught of direct oral anticoagulants, Coumadin still occupies an important place in anticoagulation. Most facilities employ POC instruments that rapidly generate the PT/INR, and most choose to confirm all INRs that exceed 4.0 by collecting venous blood and performing a plasma-based PT/INR. A 2016 report describes the R-T estimation formula designed to correlate […]

Anticoagulant Therapy

August, 2018 Quick Question

Here are the results of our August, 2018 Quick Question, answered by 93 participants:. Stem: What is the FDA-approved assay for anti-Xa DOACs? a. Thrombin time: 12% (11) b. Prothrombin time: 8% (7) c. Partial thromboplastin time: 8% (7) d. Chromogenic anti-Xa using DOAC calibrators: 72% (68) This was perhaps a “trick” question. The US […]

Anticoagulant Therapy

DOAC Measurement: CAP Today, July, 2018

If you are having any trouble with our August Quick Question on measuring DOACs, see Dr. Dorothy M. Adcock’s article, Direct Oral Anticoagulants (click or tap) in the July, 2018 issue of CAP Today.

Anticoagulant Therapy

Quick Question: DOAC Measurement

Please take a look at our August, 2018 Quick Question, “What is the FDA-approved assay for anti-Xa DOACs?” This month’s question is a quiz question with one correct answer, and not a survey. Please make your selection, responses are anonymous.

Anticoagulant Therapy

Left Atrial Appendage Closure

In response to a case-based question, has anyone seen data comparing the efficacy and safety of the left atrial appendage closure (LAAC) device Watchman with any DOAC in reducing risk of ischemic stroke in non-valvular atrial fibrillation?

Anticoagulant Therapy

Case Study: A Patient on Xarelto with Elevated D-dimer Results

In 2016, Dr. Louann Lawrence, New Orleans, communicated with a patient who had experienced a DVT and PE in 2014 and was being treated with Xarelto (rivaroxaban). The patient’s physician routinely ordered a D-dimer to assess the risk of a recurrence after discontinuing anticoagulant therapy. Following the physician’s instructions, the patient discontinues Xarelto for 24 […]

Anticoagulant Therapy

D-dimer Reference Range

Paul Smith writes, “I have a family member on Xarelto and his D-dimer reference range was 450 while taking Xarelto. What is the reference range? Hello, Mr. Smith, and thank you for your question. There is some mild confusion about the D-dimer reference intervals (reference ranges) because several distributors use varient methods. These methods result […]

Anticoagulant Therapy

May, 2018 Quick Question: DOACs

Our May, 2018 Quick Question asks, “How do you measure the oral anti-Xa anticoagulants rivaroxaban, apixaban, edoxaban, and betrixaban?” Here are the answers from our 89 respondents. Prothrombin time (PT): 4 (4%) Activated partial thromboplastin time (APTT, PTT): 3 (3%) Chromogenic anti-Xa assay with specific calibrators: 44 (49%) We don’t measure the anti-Xa anticoagulants: 38 […]

Anticoagulant Therapy

AndexXa

On May 4, the FDA approved andexanet alpha (AndexXa, Portola Pharmaceuticsls) as the first and only reversal agent for direct anti-Xa DOACs rivaroxaban (Xarelto), and apixaban (Eliquis) overdose. Tap or click MD Magazine for details. Also see the ANEXXA-A report in Siegal DM, Curnutte JT, Connolly SJ, et al. Andexanet alfa for the reversal of […]

Anticoagulant Therapy

Activated Clotting Time

Please help me (George) learn if the ACT is used for any purpose other than monitoring high dose intravenous heparin during coronary artery bypass graft surgery, percutaneous intervention, ablations, and for monitoring protamine sulfate heparin reversal at the end of the cardiac procedure. Does anyone use the ACT for routine heparin therapy monitoring or for […]

Anticoagulant Therapy

Load more

George Fritsma is a medical laboratory scientist, educator, and author. George is a member of the International Society on Thrombosis and Hemostasis, the International Society for Laboratory Hematology, and the American Society for Clinical Laboratory Science.

Cheat Sheets from George

Quick Question