D-dimer to Rule Out Pulmonary Embolism in Renal Insufficiency

BACKGROUND: D-dimer levels are often elevated in renal insufficiency. The diagnostic accuracy of D-dimer to rule out pulmonary embolism in patients with renal insufficiency is unclear. METHODS: We evaluated the data of patients presenting to our Emergency Department and receiving computed tomography angiography to rule out pulmonary embolism with measurement of D-dimer and creatinine. Glomerular filtration rate was calculated using the Chronic Kidney Disease Epidemiology Collaboration formula. RESULTS: There were 1305 patients included; 1067 (82%) had an estimated glomerular filtration rate (eGFR) exceeding 60 mL/min, 209 (16%) 30-60 mL/min, and 29 (2%) <30 mL/min. One hundred fifty-two patients (12%) had D-dimer below 500 mu g/L. eGFR (R = -0.1122) correlated significantly with D-dimer (P <.0001). One hundred sixty-nine patients (13%) were found to have pulmonary embolism. Sensitivity of D-dimer for patients with an eGFR >60 mL/min was 96% (confidence interval [CI], 0.93-0.99) and 100% (CI, 100-100) for those with 30-60 mL/min, while specificity decreased significantly with impaired renal function. Area under the curve of the receiver operating characteristic for D-dimer was 0.734 in patients with an eGFR of >60 mL/min, and 0.673 for 30-60 mL/min. CONCLUSIONS: D-dimer levels were elevated in patients with an eGFR <60 mL/min, but proved to be highly sensitive for the exclusion of pulmonary embolism. However, because almost all patients with impaired renal function had elevated D-dimer irrespective of the presence of pulmonary embolism, studies should be performed to determine renal function-adjusted D-dimer cutoffs. (C) 2014 Elsevier Inc. All rights reserved.