Procalcitonin serum levels in perinatal bacterial and fungal infection of preterm infants

Aim: To determine reference values for procalcitonin (PCT) and C-reactive protein (CRP) for gestational age and to use these parameters as diagnostic markers of perinatal bacterial and fungal infection. Methods: PCT and CRP serum levels were measured in a case-control study in a group of 35 low birthweight infants (<34 wk of gestation). 27 babies (77%) had clinical signs of infection confirmed by positive blood cultures and were compared to 8 (23%) uninfected matched patients. Seventeen (63%) of them had bacterial infection and 10 (37%) had fungal infection (Candida). Serum PCT (Brahms Diagnostika) and CRP (Immunoassay Vitros 950) were measured serially at 3, 7 and 10 d of life. Results: At any time, PCT and CRP levels were significantly higher in neonates with perinatal infection (p < 0.05) (>0.7 ng ml(-1) and >1 mg dl(-1), respectively). PCT showed a more rapid response to infection (9.3 +/- 1.5 ng ml(-1)), especially to bacterial infection (10.8 +/- 1.4 ng ml(-1)), than CRP (1.5 +/- 0.5 mg dl(-1)) (sensitivity 99% vs 88%). Lower sensitivity was noted for both parameters, PCT and CRP, to follow babies with fungal infection (6.7 +/- 0.8 ng ml(-1) and 0.9 +/- 0.7 mg dl(-1), respectively) (sensitivity 77% vs 58%). Conclusion: This study gives PCT reference values in preterm babies with perinatal infection. In these babies, PCT seems to be more sensitive than CRP as a diagnostic marker of infection. Both parameters can be used alone or in combination for a better identification and follow-up of bacterial and fungal infection during the perinatal period.