Receiver operating characteristic curves for comparison of serial neutrophil band forms and C reactive protein in neonates at risk of infection.

Abstract

The performance of indirect indices of infection in the newborn vary because of differences in techniques, including diagnostic cut off levels. We have compared serial neutrophil band cell counts with C reactive protein measured by rate nephelometry. The 'gold standard' was a positive culture and the performance of the tests was compared by the technique of receiver operating characteristics (ROC) as well as sensitivity and specificity.A total of 172 septic screens were performed in 56 patients. The operational diagnostic cut off values were: C reactive protein >8 mg/l, inmature:total neutrophil ratio (I:T ratio) >02, and band count >5%. Compared with the sensitivity of C reactive protein (710/), I:T ratio (34%) was significantly different but band count (69%) was not. The specificity of C reactive protein (72%) was better than band count (39%) but no better than I:T ratio (73%). ROC curves were constructed for all possible diagnostic cut off values of the tests and superior performance was demonstrated for C reactive protein compared with band count and I:T ratio.We conclude that C reactive protein is a useful early indicator of infection in neonates and that ROC curves permit comprehensive and graphic comparison between tests and the calculation of optimal diagnostic cut off values.

C-reactive protein-guided approach may shorten length of antimicrobial treatment of culture-proven late-onset sepsis: an intervention study

“…Serum CRP levels remain high as long as the injurious stimulus persists but, due to its short half-life (aproximatelly 20 hours), they fall rapidly after elimination of the (often microbial) source of inflammation [16,24,25]. During the neonatal period, an established upper normal CRP level of 10 mg/L has been identified in most studies as indicating the presence of sepsis or infection [8,21,23,[26][27][28], but other authors have used different upper normal reference levels [21,29,30]. Conflicting values have added much to the confusion and uncertainty to the use of CRP in clinical practice.…”

Immunologic Parameters in Cord Blood Indicating Early-Onset Sepsis

“…Sensitivity and specificity for all possible cut-off values was calculated to con struct the receiver operating characteristic [20]. The optimal value for detection of sep sis, sensitivity and specificity of each parame ter are shown (table 1).…”

Randomised controlled study of clinical outcome following trophic feeding

“…The total number of days when the C reactive protein was greater than 10 mg/l (upper normal limit of local laboratory) was also recorded. C reactive protein is a sensitive non-specific acute phase protein that increases in serum concentration during episodes of sepsis 13. It was measured daily in infants receiving assisted ventilation and then later when sepsis was suspected.…”