Title: Lack of specificity of procalcitonin for sepsis diagnosis in premature infants
Abstract: M Hatherill and colleagues (Dec 13, p 1749)1Hatherill M Jones G Lim E Tibby SM Murdoch IA Procalcitonin aids diagnosis of adrenocortical failure.Lancet. 1997; 350: 1749-1750Summary Full Text Full Text PDF PubMed Scopus (31) Google Scholar emphasised the use of procalcitonin in differentiating conditions that may mimic septicaemia. They highlight procalcitonin as a specific marker of bacterial sepsis in paediatric intensive care units. However, to our knowledge, the specificity of this new marker has not been evaluated in premature infants.2Assicot M Gendrel D Carsin H Raymond J Guilbaud J Bohuon C High serum procalcitonin concentrations in patients with sepsis and infection.Lancet. 1993; 341: 515-518Summary PubMed Scopus (1744) Google Scholar, 3Gendrel D Assicot M Raymond J et al.Procalcitonin as a marker for the early diagnosis of neonatal infection.J Pediatr. 1996; 128: 570-573Summary Full Text Full Text PDF PubMed Scopus (245) Google Scholar We have therefore looked at the use of serum procalcitonin as a discriminating prognostic factor in severe septic states in such a paediatric population. We report serum concentrations of procalcitonin, assessed by a specific immunoluminometric assay (Lumitest PCT, Brahms Diagnostica GMBH, Berlin, Germany), in 150 newborn babies (gestational age 25–41 weeks) at risk of bacterial infection during the first 10 days of life (mean postnatal age [SD, range] 2·3 [2·4, 0-10] days). On the basis of clinical and laboratory findings, 19 newborn babies with a positive bacteriological result in blood or cerebrospinal fluid cultures or with characteristic clinical symptoms of infection, were defined as having infection. Differences between groups were assessed with the Mann Whitney U test. Serum procalcitonin values were significantly higher in the infected group than in the non-infected group (median 42·0 vs 4·5 ng/mL, respectively; p=0·0004). These values varied greatly in both groups. With a threshold value of 5 ng/mL,1Hatherill M Jones G Lim E Tibby SM Murdoch IA Procalcitonin aids diagnosis of adrenocortical failure.Lancet. 1997; 350: 1749-1750Summary Full Text Full Text PDF PubMed Scopus (31) Google Scholar, 3Gendrel D Assicot M Raymond J et al.Procalcitonin as a marker for the early diagnosis of neonatal infection.J Pediatr. 1996; 128: 570-573Summary Full Text Full Text PDF PubMed Scopus (245) Google Scholar sensitivity for the diagnosis of bacterial infection was 84% whereas specificity was strikingly low (50%). The lack of specificity was in part explained by significantly higher procalcitonin in non-infected infants with respiratory distress syndrome (p=0005) or haemodynamic failure (p=0·002) than in non-infected infants who had neither of these conditions; Serum PCT values were highly variable in this latter group (figure). No significant effect on PCT of birthweight, gestational age, sex, mode of delivery, or perinatal asphyxia could be detected. We suggest that serum PCT concentrations should be interpreted with caution in premature and term infants admitted to a neonatal intensive care unit. Our findings show that specific events (eg, respiratory distress syndrome and haemodynamic failure) determine serum concentration of PCT during the first 10 days of life, independently of any.