Procalcitonin as a parameter of disease severity and risk of mortality in patients with Plasmodium falciparum malaria.

The serum levels of procalcitonin (PCT) in Plasmodium falciparum malaria were evaluated for clinical significance in 66 nonimmune and semi-immune patients. Of the 66 patients, 36 had uncomplicated malaria, 24 had severe and complicated malaria, and 6 had fatal malaria (5 from previous studies). Pretreatment PCT concentrations were closely correlated with parasitemia. Concentrations were lowest in semi-immune patients with uncomplicated malaria, compared with those in nonimmune patients (geometric mean concentrations [GMCs], 1.07 and 2.37 ng/mL, respectively), and were highest in severe and complicated cases (GMC, 10.67 ng/mL; P<.001 among all subgroups). Six of 7 patients with PCT concentrations >25 ng/mL died. PCT concentrations decreased on day 2 of treatment in survivors but not in patients with fatal outcome. Thus, repeated PCT measurements may provide useful prognostic information, especially in medical centers that are not experienced in parasite density determination.