Category: Laboratory medicine

Studies have shown that starting anticoagulant therapy can decrease D-dimer levels by approximately 25% within 24 hours. This significant reduction means blood thinners can affect a D-dimer test, potentially compromising its accuracy for diagnosing active blood clots.

Heparin is a critical anticoagulant used in phlebotomy, with green-top blood collection tubes containing either its sodium or lithium salt to keep blood from clotting. Understanding **how does heparin prevent blood from clotting by phlebotomy** is key to appreciating its role in producing accurate laboratory test results for plasma chemistry.

While the activated partial thromboplastin time (aPTT) is the standard test for monitoring unfractionated heparin therapy, this anticoagulant can also cause a significant, though often artifactual, prolongation of the prothrombin time (PT). This complex interaction is crucial for healthcare professionals to understand, especially during transitions to oral anticoagulants like warfarin.

Heparin, a fast-acting anticoagulant, is widely used to prevent and treat blood clots. Unlike the oral anticoagulant warfarin, it does not require monitoring via the International Normalized Ratio (INR), leading many to question: Does heparin affect PT or PTT? The answer lies in its specific mechanism of action within the body's complex coagulation cascade.

The FDA has received numerous adverse event reports, including one death, related to biotin interference with lab tests, particularly the cardiac marker troponin [1.6.1, 1.9.4]. This highlights a critical question for supplement users: **what can biotin interfere with?**