Optimal D-dimer value for acute deep vein thrombosis screening in the lower limb in cases with carcinomas

D-dimer is a recognized tool for screening venous thromboembolism, with the standardized cutoff value for the possibility of acute deep vein thrombosis (DVT) being 1 μg/mL. For patients above the threshold, noninvasive ultrasonography examination is recommended. However, considering that carcinomatous status potentially increases D-dimer levels and shortage of ultrasonography technologists in Japan, the cutoff value should be optimized for patients with carcinomas. In total, 1124 consecutive cases from 2017 to 2021 in our division were evaluated. In the carcinoma group (n = 225), no significant association was found between the carcinoma stage (0-3 vs 4) and D-dimer levels (P = .54); therefore, staging was not considered in determining the optimal cutoff value. The median D-dimer level differed by 3.1 μg/mL between carcinomatous and non-carcinomatous states in cases without acute DVT in lower limbs. Thus, we tested the cutoff value of increasing D-dimer concentrations, and a cutoff value of 5 μg/mL demonstrated a high specificity of 42.9%. In screening for acute DVT in lower limbs for carcinoma cases, the D-dimer cutoff value may be increased from 1 to 5 μg/mL.