I:T ratios during the first 5 days of life are less than ____ in 96% of healthy premature infants with a gestational age of 32 weeks or less.

• A. 0.4
• B. 0.3
• C. 0.1
• D. 0.2

Answer: (D)

The I/T ratio measures the proportion of immature neutrophils (bands, metamyelocytes, etc.) to the total neutrophil count. In the first days of life, especially in very preterm infants, a low I/T ratio is typical. Data show that about 96% of healthy premature infants ≤32 weeks gestation have an I/T ratio below 0.2 during the first five days. So the value that fits this normal distribution is 0.2. Clinically, an I/T ratio higher than 0.2 can raise concern for infection or sepsis in a neonate, prompting further evaluation, while the other thresholds would not match the reported normal range.