Distinguishing immune-mediated thrombotic thrombocytopenic purpura from septic disseminated intravascular coagulation using plasma levels of haptoglobin and factor XIII activity

How We Interpret Thrombosis with Thrombocytopenia Syndrome?

“…On the other hand, FDP was 8.5 µg/mL and 16.7 µg/mL (reference value, <5.0 µg/mL), and D-dimer was 4.1 µg/mL and 7.1 µg/mL (reference value, <1.0 µg/mL), representing moderately high values. TAT level, as a marker of coagulation activation, was 9.6 ng/mL and 10.8 ng/mL (reference value, <3.9 ng/mL), and PIC, a fibrinolytic activation marker, was 1.7 and 2.0 µg/mL (reference value, <0.8 µg/mL), only slightly above the upper limit [117,118]. Because TTP and DIC often show similar findings from coagulation and fibrinolysis tests, differentiating between TTP and DIC based solely on coagulation and fibrinolysis test findings is challenging.…”

“…The characteristics of coagulation and fibrinolysis tests in TTP have been reported [117,118]. Median coagulation and fibrinolysis test values reported in these reports were as follows: platelet count was significantly decreased to 9000/µL and 12,000/µL, PT-INR was within the normal range at 1.06 and 1.09 (reference value, 0.90-1.15), and APTT was within the normal range at 30 s and 31 s (reference value, 24.0-37.7 s).…”

“…Distinguishing between the two using existing scoring systems is also very difficult. For example, approximately 30% of TTP patients meet the DIC diagnostic criteria set by the International Society on Thrombosis and Haemostasis, and 70% of DIC patients meet one or more items of the French score [118]. Clearly differentiating between the two using the PLASMIC score is difficult.…”

“…We examined the differentiation between TTP and septic DIC based on the localization of the thrombus formation and the degree of coagulation activation [118]. In this report, we subtracted haptoglobin (mg/dL) from factor XIII activity (%) and considered TTP present for values ≥ 60 and DIC for values < 60 (Figure 2).…”

“…The sensitivity and specificity of the index are high at 94.3% and 86.7%, respectively, and both factor XIII activity and haptoglobin alone offer high sensitivity and specificity. We call this evaluation index the TTP/DIC index [118]. Decreased factor XIII activity has been observed in other types of DIC [192], and haptoglobin is thought to be decreased in any type of TMA as in TTP because of the strong hemolysis due to platelet thrombus.…”