The ratio of immature to total neutrophils is used as a sensitive marker for which condition in newborns?

• A. Hypoglycemia
• B. Early onset sepsis
• C. Hypoxemia
• D. Polycythemia

Answer: (B)

The important idea is that an elevated immature-to-total neutrophil ratio reflects a left shift, meaning the bone marrow is releasing more immature neutrophils in response to inflammation or infection. In newborns with early onset sepsis, the body responds to bacterial invasion by mobilizing neutrophils quickly, often pushing out immature forms (bands and other precursors) into circulation. This raises the IT ratio even before culture results are available, making it a sensitive marker for this condition in the first days of life. Other listed conditions—hypoglycemia, hypoxemia, and polycythemia—do not typically provoke a neutrophil left shift to the same extent, so they aren’t associated with a rising IT ratio in the same way.