From the Research
D-dimer levels can indeed be affected by blood transfusions, and clinicians should consider this potential interference when interpreting D-dimer results in recently transfused patients. When a patient receives blood products, particularly those containing fibrin degradation products like fresh frozen plasma or older stored red blood cells, their D-dimer levels may temporarily increase 1. This occurs because transfused blood products can contain pre-formed D-dimer or trigger coagulation processes in the recipient. The effect is generally more pronounced with massive transfusions or when multiple blood products are administered.
The elevation typically resolves within 24-48 hours after transfusion as the body clears these products. This potential interference is important to consider when interpreting D-dimer results in recently transfused patients, as it may lead to false positive results when using D-dimer to rule out conditions like deep vein thrombosis or pulmonary embolism 2. Clinicians should take into account the timing of blood transfusions when evaluating D-dimer results and may need to rely more heavily on other diagnostic methods or repeat testing after the effects of transfusion have subsided.
Some key points to consider include:
- D-dimer is a marker of coagulation and fibrinolytic system activation, and its level can be affected by various factors, including age, pregnancy, and cancer 1
- The diagnostic accuracy of D-dimer levels can be improved by adjusting the cutoffs according to patient characteristics, such as age, pretest probability, pregnancy, renal function, or cancer 1
- D-dimer levels can also predict clinical severity of certain conditions, such as COVID-19, and escalated anticoagulation based on D-dimer levels can be associated with a lower risk of mortality in patients with severe COVID-19 1
- Clinicians should be aware of the limitations of D-dimer assays, including the lack of standardization and the potential for false positive results in certain clinical scenarios 3.
Overall, clinicians should exercise caution when interpreting D-dimer results in recently transfused patients and consider the potential for false positive results. By taking into account the timing of blood transfusions and using a combination of diagnostic methods, clinicians can make more accurate diagnoses and provide effective treatment for patients with suspected thrombotic disorders 4.