From the Research
D-dimer levels can be elevated in some patients with influenza (flu) infection, particularly in severe cases with complications like pneumonia or those requiring hospitalization, as shown in a study from 2011 1. While not a specific marker for flu, D-dimer may increase during influenza infection due to the inflammatory response and activation of the coagulation system. The flu virus can trigger systemic inflammation that leads to endothelial damage and activation of blood clotting pathways, resulting in increased fibrin formation and breakdown, which is measured by D-dimer tests. Some key points to consider:
- D-dimer elevation is not diagnostic for flu as it can be elevated in many other conditions including COVID-19, bacterial infections, cancer, pregnancy, and following surgery.
- A study from 2021 2 highlights the importance of considering anticoagulant therapy in patients with severe influenza infection, as they may be at risk of developing venous thromboembolism (VTE).
- Another study from 2021 3 suggests that high D-dimer levels, with subsequent downtrend correlating with clinical deterioration, may be an indicator of fibrinolysis suppression.
- It is essential to use more specific tests like PCR or rapid antigen tests for flu diagnosis, rather than relying on D-dimer levels alone.
- The accuracy of D-dimer test results is crucial, and laboratories should be equipped to identify suspicious test results in a timely manner and avoid adverse events, as reported in a case study from 2021 4.