Renal Function-Adjusted D-Dimer Levels in Critically Ill Patients With Suspected Thromboembolism

Area of Science:

• Medical Diagnostics
• Clinical Chemistry
• Nephrology

Background:

• Thromboembolic disease diagnosis often relies on D-dimer testing and clinical scores.
• Renal dysfunction can elevate D-dimer levels, complicating diagnosis.
• Validated D-dimer cutoff levels adjusted for estimated glomerular filtration rate (eGFR) are needed.

Purpose of the Study:

• To validate previously suggested eGFR-adjusted D-dimer cutoff levels.
• To assess the impact of renal dysfunction type on test characteristics.
• To improve diagnostic accuracy for thromboembolic disease in patients with impaired kidney function.

Main Methods:

• Retrospective analysis of electronic healthcare records from emergency department patients.
• Inclusion of 14,477 patients suspected of having thromboembolic disease.
• Comparison of conventional D-dimer cutoff (500 µg/L) with eGFR-adjusted cutoffs (e.g., >333 µg/L for eGFR >60, >1,306 µg/L for 30-60, >1,663 µg/L for <30).

Main Results:

• Renal dysfunction was present in 9.4% of the 14,477 patients.
• eGFR-adjusted D-dimer levels maintained high negative predictive value (>99%) and sensitivity (91.2%-93.4%).
• Adjusted levels showed improved specificity (42.7%-50.7%) compared to the conventional cutoff, reducing false positives in patients with eGFR <60 mL/min/1.73 m².

Conclusions:

• eGFR-adjusted D-dimer cutoff levels are feasible, safe, and reliable for diagnosing thromboembolic disease.
• These adjusted levels are effective even in patients with acute kidney injury or acute-on-chronic renal dysfunction.
• Utilizing eGFR-adjusted cutoffs can significantly reduce the false-positive rate in patients with reduced kidney function.