Validation of c-reactive protein in the early diagnosis of neonatal sepsis in a tertiary care hospital in Kenya

Abstract

To evaluate utility of C-reactive protein (CRP) in the early diagnosis of neonatal sepsis in a tertiary care Newborn Unit in Kenya. Cross-sectional study. Newborn Unit, Kenyatta National Hospital. All neonates admitted to Newborn Unit, Kenyatta National Hospital during the study period with suspected sepsis based on specified clinical criteria. Of the 310 infants, there were 83 episodes of proven sepsis and 94 episodes of probable sepsis. Using the standard CRP cut-off value of 5 mg/dl, a sensitivity of 95.2% in proven sepsis and 98.9% for probable septic episodes were noted. In proven sepsis, a specificity of 85.3%, positive predictive value of 80.6%, and a negative predictive value of 96.5% were noted. In probable sepsis, a specificity of 83.3%, positive predictive value of 80.9% and a negative predictive value of 99.1% were noted. The overall accuracy in proven sepsis was 96.5%, and in probable sepsis was noted to be 99.1%. Sub-analysis showed a lower positive predictive value (61.5%) for early onset sepsis compared to 93% for late onset sepsis. Repeat CRP tests were done in 33 babies. Twenty two of the 29 with proven/probable infection had a ten-fold increase in CRP levels, but levels were noted to be low or reducing in seven (24.1%) babies showing signs of improvement clinically. Using a receiver operator characteristic curve, the optimal cut-off point for CRP was found to be 5 mg/dl. Serum CRP is an accurate indicator of neonatal sepsis, with high sensitivity, specificity and predictive values, at the standard cut-off of 5. CRP is a better screening test for late-onset than early-onset neonatal sepsis. The standard recommended CRP cut -off point of 5 is appropriate for local use.