Is FDP reliable for diagnosing PTE?

–Comparison of FDP and D-dimer–

Abstract

Background: D-dimer has high sensitivity for pulmonary thrombo embolism (PTE), and is as reliable as applying the Wells criteria to rule out PTE, which is a serious disease and sometimes fatal. FDP is another widely used blood marker of fibrin deposition and fibrinolytic activation that is used to rule out PTE. It has been reported that D-dimer is superior to FDP in ruling out PTE, at least outside Japan. However, no published report compares D-dimer and FDP for ruling out PTE using the methods of measurement and cut-off values adopted in Japan, and the frequency of PTE in Japan differs from other countries. We therefore sought to compare and evaluate the sensitivities of FDP and D-dimer for PTE for the first step of constructing Japanese original algorithm for diagnosing PTE. Methods: We analyzed 59 patients who were hospitalized in Tenri hospital and were diagnosed with PTE during January 2005 and December 2010. All 59 patients underwent examination for both FDP and D-dimer. For 52 of the 59 PTE patients we were able to obtain Wells criteria scores. We also analyzed 178 patients who were not diagnosed with PTE and examined both their FDP and D-dimer during January 2011. Our main purpose was to compare the sensitivities of FDP and D-dimer for the 59 PTE patients. We also compared the sensitivities of FDP and D-dimer for PTE patients classified as the low-risk group by Wells criteria, and as the intermediate to high-risk group by Wells criteria. We also drew the ROC curves of FDP and D-dimer for PTE and compared the AUCs of the two ROC curves. Results: In 59 PTE patients, the sensitivities of FDP and D-dimer for PTE were respectively 78% and 95%. In patients classified into the low-risk group, D-dimer has a sensitivity of 100% (9/9 patients), but FDP has a sensitivity of 78% (7/9 patients). In patients classified into the intermediate to high-risk group, the sensitivities of FDP and D-dimer for PTE were respectively 74% and 93%. The AUCs of FDP and D-dimer were respectively 0.688 and 0.745. Conclusion: According to the present study, D-dimer is more sensitive than FDP at ruling out PTE. This study also suggests that D-dimer is more reliable than FDP in ruling out PTE.