Which of the following is the MOST sensitive and specific neonatal screening test for early-onset bacterial sepsis when the infant appears symptomatic at 12 hours of life?

• A C-reactive protein (CRP)
• B Complete blood count with I:T ratio >0.2
• C Serum procalcitonin
• D Blood culture ✓

Explanation

Blood culture remains the gold standard for diagnosing neonatal sepsis and is the most specific test. Although procalcitonin and CRP are useful inflammatory markers, they lack sensitivity in early onset sepsis (<12–24 hours) and rise later in the course. The I:T ratio >0.2 has moderate sensitivity. Blood culture identifies the causative organism and guides antibiotic therapy, making it the definitive diagnostic test.

Reference: Ghai Essential Pediatrics, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.