Plasmic score applicability for the diagnosis of thrombotic microangiopathy associated with ADAMTS13-acquired deficiency in a developing country

BACKGROUND: Thrombotic thrombocytopenic purpura (TTP) is a potentially fatal disease that requires early diagnosis and treatment that can be made possible by applying the PLASMIC score. This study aims to evaluate this score applicability for patients with suspected TTP in a developing country. METHODS: This was a retrospective study performed at a tertiary hospital in the northeastern region of Brazil. Patients were analyzed in two groups: ADAMTS13 activity <10% and activity >10%. Patients were stratified according to the PLASMIC score, and the level of agreement between the PLASMIC score and the ADAMTS13 activity was evaluated. RESULTS: Eight patients with thrombotic microangiopathy were included. Four patients had ADAMTS13 activity <10%, all with a PLASMIC score =6. The other four had ADAMTS13 activity >10%, all with a score <6. Based on a score =6 for presumptive diagnosis of TTP, we attained a 100% diagnostic accuracy in our sample. The PLASMIC score was also able to accurately predict response to plasma exchange and the risk of long-term unfavorable outcomes. CONCLUSIONS: The reproducibility of the PLASMIC score was quite satisfactory in our sample. It accurately discriminates between patients who had ADAMTS13 deficiency and those with normal enzyme activity, precluding the need for specific laboratory evaluation, which is not always available. This score can be useful for an early diagnosis and indicates which patients will benefit from the treatment in developing countries.