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Plasmic Score

Predicts ADAMTS13 deficiency in suspected thrombotic thrombocytopenic purpura (TTP) with high discrimination

EVIDENCE APPRAISAL

The PLASMIC Score was derived by Bendapudi et al and externally validated in a study with an independent cohort of 112 consecutive hospitalized patients with suspected thrombotic microangiopathy and appropriate ADAMTS-13 testing (including 21 patients with TTP diagnosis). The PLASMIC model predicted severe ADAMTS-13 deficiency with a c statistic of 0.94 (0.88-0.98). When dichotomized at high (scores 6-7) vs. low-intermediate risk (scores 0-5), the model predicted severe ADAMTS-13 deficiency with positive predictive value 72%, negative predictive value 98%, sensitivity 90% and specificity 92%.

In the low-intermediate risk group (scores 0-5), there was no significant improvement in overall survival associated with plasma exchange. The PLASMIC Score had excellent applicability, discrimination and calibration for predicting severe ADAMTS-13 deficiency. The clinical algorithm allowed identification of a subgroup of patients who lacked a significant response to empiric treatment.

Reference

  1. Bendapudi PK, Hurwitz S, Fry A, et al. derivation and external validation of the plasmic score for rapid assessment of adults with thrombotic microangiopathies: a cohort study. Lancet Haematol. 2017;4(4):e157-e164.
  2. Li A, Khalighi PR, Wu Q, Garcia DA. External validation of the PLASMIC score: a clinical prediction tool for thrombotic thrombocytopenic purpura diagnosis and treatment. Thromb Haemost 2018;16(1):164-169

French Score

Each item is associated with one point (+1)

aResults correspond to those of the derivation cohort and those of a validation by (French score) the bootstrap resampling technique (internal validation)3,4 or (PLASMIC score) different samples of patients from the same institution (internal validation) or from a different institution (external validation).

bThe French score considered patients with a thrombotic microangiopathy syndrome (which includes hemolysis with schistocytes in the definition) and assumes that there is no history of or clinical evidence for associated cancer, transplantation, or disseminated intravascular coagulopathy; so, these items are intrinsic to the score.

cMCV was not incorporated in the French score.

References

  1. Coppo P, et al. PLoS One. 2010;5(4):e10208
  2. Bendapudi PK, et al. Lancet Haematol. 2017;4(4):e157-e164
MAT-AE-2200643-V2-OCT-23