1. What is the I/T Ratio?

The I/T (immature to total neutrophil) ratio is a hematologic parameter used primarily in neonatal intensive care to assess for sepsis. It compares the number of immature neutrophils to the total neutrophil count.

2. How Does the Calculator Work?

The calculator uses the I/T ratio formula:

Where:

• \( Immature\_neutrophils \) — Count of immature neutrophils (bands and earlier forms)
• \( Total\_neutrophils \) — Count of all neutrophils (mature + immature)

Explanation: The ratio helps identify a left shift in neutrophil maturation, which can indicate infection or inflammation.

3. Importance of I/T Ratio

Details: In neonates, an I/T ratio >0.2 is often considered abnormal and may suggest sepsis, particularly in the first 72 hours of life.

4. Using the Calculator

Tips: Enter the absolute counts of immature neutrophils and total neutrophils from a complete blood count with differential. Both values must be positive numbers, and immature count cannot exceed total count.

5. Frequently Asked Questions (FAQ)

Q1: What is a normal I/T ratio in neonates?
A: Typically <0.2 in term infants, though ranges vary slightly by gestational age and postnatal hours.

Q2: How sensitive is I/T ratio for neonatal sepsis?
A: Sensitivity ranges from 60-90% depending on study and cutoff used, usually combined with other markers.

Q3: Does I/T ratio change with age?
A: Yes, normal values decrease after the first few days of life as hematopoiesis stabilizes.

Q4: What conditions besides sepsis can elevate I/T ratio?
A: Maternal chorioamnionitis, perinatal stress, hemolysis, and some congenital infections.

Q5: How often should I/T ratio be repeated?
A: Serial measurements every 12-24 hours may help track response to treatment in suspected sepsis.