Laboratory diagnosis of neonatal sepsis

Laboratory diagnosis of neonatal sepsis continues to be a confusing issue- numerous tests but most of them lacking precise sensitivity and specificity. Simple blood counts are easy to do but are not specific while the band count and I:T ratio assessment needs an expert, making it difficult to be used routinely. CRP is a simple investigation but one should understand its pitfalls so that it is judiciously used. Indiscriminate use of CRP is leading to widespread antibiotic overuse and development of resistant organisms. Interleukin 6, neutrophil CD64 index, procalcitonin and NRBC count are some promising newer screening tests which are being evaluated. Automated blood cultures have proved to be very sensitive and rapid in reporting compared to conventional blood cultures. Finally PCR of 16s rRNA gene along with bacterial probes has found its place in the diagnosis of sepsis with a high degree of accuracy. A combination of screening tests along with the clinical signs is useful to initiate antibiotics while the duration or cessation of antibiotics should be guided by the blood cultures.