What is the primary investigation of choice for diagnosing neonatal sepsis?

The primary investigation of choice for diagnosing neonatal sepsis is blood culture. This is essential because blood culture is a definitive method for identifying the causative microorganisms responsible for sepsis in neonates. It involves taking a sample of the infant's blood and culturing it in a laboratory setting to check for the presence of bacteria or fungi.

In the context of neonatal health, early detection of sepsis is crucial as the condition can progress rapidly and may lead to severe complications or death. Blood cultures help initiate appropriate antibiotic therapy based on the identified organism, significantly improving outcomes.

While a complete blood count may provide some supportive evidence, such as identifying elevated white blood cell counts or immature neutrophils, it is not specific enough to confirm sepsis. Imaging studies, such as chest X-rays or cranial ultrasounds, may be used to rule out other conditions or complications, but they do not specifically diagnose sepsis. Therefore, blood culture remains the cornerstone of diagnosis for this critical condition in newborns.