Procalcitonin and C-reactive protein as predictors of blood culture positivity among hospitalised children with severe pneumonia in Mozambique.

OBJECTIVES: To evaluate the benefits of using procalcitonin (PCT) and C-reactive protein (CRP) as pre-screening tools to predict blood culture positivity among Mozambican children with clinical severe pneumonia (CSP).
METHODS: 586 children <5 years with CSP and no concurrent malaria fulfilled criteria to be included in the study groups. We determined PCT and CRP for all children with positive bacterial culture (BC+ group, n = 84) and of a random selection of children with negative bacterial culture (BC- group, n = 246).
RESULTS: PCT and CRP levels were higher in the BC+ group than the BC- one (PCT: median 7.73 versus 0.48 ng/ml, P < 0.001; CRP: 177.65 mg/l vs. 26.5 mg/l, P < 0.001). In multivariate analysis, PCT was the only independent predictor of the group. To be used as pre-screening tool, PCT presented higher specificities for predetermined sensitivities (≥85%) than CRP. Pursuing a sensitivity of 95%, PCT could reduce the need for bacterial culture by 49% and overall diagnosis costs by 7-35% [assuming variable costs for PCT measurement (ranging from 10 to 30 USD) and a fixed cost of 72.5 USD per blood culture].
CONCLUSIONS: Among hospitalised children with CSP and absence of concurrent malaria, PCT pre-screening could help reduce the number of blood cultures and diagnosis costs by specifically targeting patients more likely to yield positive results.