1. What is the I/T Ratio?

The I/T (Immature to Total neutrophil) ratio is a valuable marker for assessing neonatal sepsis in NICU settings. It compares the number of immature neutrophils to the total neutrophil count in a newborn's blood sample.

2. How Does the Calculator Work?

The calculator uses the I/T ratio formula:

Where:

• \( Immature\ Neutrophils \) — Count of band forms and earlier neutrophil precursors
• \( Total\ Neutrophils \) — Sum of mature and immature neutrophils

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

3. Importance of I/T Ratio in NICU

Details: In neonates, an I/T ratio >0.2 is considered abnormal and may suggest early-onset sepsis. It's particularly useful when clinical signs are subtle or non-specific.

4. Using the Calculator

Tips: Enter the absolute counts of immature neutrophils and total neutrophils from a complete blood count (CBC) with differential. Both values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is a normal I/T ratio in newborns?
A: Typically <0.2 in healthy term infants. Values >0.2 suggest possible infection and warrant further evaluation.

Q2: How does gestational age affect I/T ratio?
A: Premature infants may have slightly higher normal ranges. Always consult gestational age-specific reference ranges.

Q3: When should I/T ratio be measured?
A: When evaluating for sepsis, especially in neonates with risk factors like maternal fever, prolonged rupture of membranes, or clinical signs of infection.

Q4: Are there limitations to I/T ratio?
A: Yes. It has moderate sensitivity and specificity. Always interpret in clinical context with other markers like CRP, procalcitonin, and clinical signs.

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