[Procalcitonin, a marker of bacterial meningitis in children].

Procalcitonin (PCT) is a new marker connected to systemic bacterial infection. Blood values are parallel to the severity of the disease. In the present Knowledge on PCT, the usefulness is focused on acute pediatric pathology, ICU, and the follow up of grafts and surgery. This paper dwells on the interest in the differential diagnosis for meningitis (viral versus bacterial). At the opposite of CRP and IL6, a very clear cut off for all the cases has been found. The cut off in this study is about 2-3 micrograms/l. PCT, at the difference of cytokines is a very stable molecule in the blood sample. Also a very small quantity of serum (or plasma) 20 microliters is sufficient for one assay. In the future, a point of care assay will be available and should be very interesting in the emergency wards (pediatric or adult ICU). The origin of PCT seems to be--but perhaps not exclusively--mononuclear cells. The absence of an animal model (except monkeys) is actually a difficulty to progress.