Any of 3 specific routine lab tests may help to distinguish between acquired thrombotic thrombocytopenic purpura (aTTP) and septic disseminated intravascular coagulation (DIC), according to research published in the Journal of Intensive Care Medicine.

If not treated quickly with therapeutic plasma exchange, aTTP can have poor outcomes, and delayed therapeutic intervention due to misdiagnosis can lead to treatment failure. Furthermore, aTTP can be difficult to distinguish from septic DIC because patients with either issue can present with thrombocytopenia, microvascular thrombosis, or organ failure.

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Although ADAMTS13 lab results distinguish between aTTP and septic DIC, this test can take time to process — up to 7 days in Japan. As there is evidence that some coagulation and fibrinolysis markers also distinguish between the 2 issues, researchers queried the thrombotic microangiopathy registry in Japan to determine whether these markers, or any others, are useful for distinguishing between aTTP and septic DIC.

Data from 138 patients with aTTP and 46 patients with septic DIC were included. Patients in the aTTP group were more likely to be younger (median age, 55.5 years vs 70.5 years) and to have lower ADAMTS13 activity (< .5% vs 33.1%) compared with patients in the septic DIC group.

Platelet counts (P <.001) were lower, and both international normalized ratio of prothrombin time (P <.001) and activated partial thromboplastin time (P <.001) were lower and shorter, in the aTTP group compared with the septic DIC group; antithrombin values (P <.001), however, were higher among patients with aTTP and approached normal measurements.

Although fibrinogen degradation product (FDP) and D-dimer levels were elevated in both groups, patients with septic DIC had higher levels compared with patients with aTTP (P <.001).

Severe thrombocytopenia, antithrombin levels, and degree of FDP elevation were each distinguishing factors of aTTP.

Taken together, these results showed that aTTP and septic DIC were distinguishable using markers other than ADAMTS13 activity, the researchers noted. However, they added that in order to “confirm the usefulness of these parameters, further analysis is required.”

Reference

1.     Sakai K, Wada H, Nakatsuka Y, Kubo M, Hayakawa M, Matsumoto M. Characteristics behaviors of coagulation and fibrinolysis markers in acquired thrombotic thrombocytopenic purpura [published online January 22, 2020]. J Intensive Care Med. doi:10.1177/0885066619899637