1. What is the IT Ratio?

The IT (Indirect/Total) Bilirubin Ratio is used in neonatal practice to help differentiate between different causes of jaundice. It compares the indirect (unconjugated) bilirubin fraction to the total bilirubin level.

2. How Does the Calculator Work?

The calculator uses the simple formula:

Where:

• \( Indirect\ Bilirubin \) — Unconjugated bilirubin level (mg/dL)
• \( Total\ Bilirubin \) — Sum of direct and indirect bilirubin (mg/dL)

Explanation: The ratio helps clinicians determine if hyperbilirubinemia is primarily due to unconjugated or conjugated bilirubin.

3. Clinical Significance in NICU

Details: In neonates, an IT ratio >0.8 suggests unconjugated hyperbilirubinemia (common in physiological jaundice or hemolytic disease), while lower ratios may indicate cholestasis or other liver disorders.

4. Using the Calculator

Tips: Enter both indirect and total bilirubin values in mg/dL. The indirect value must be ≤ total bilirubin. Results are displayed as a decimal between 0 and 1.

5. Frequently Asked Questions (FAQ)

Q1: What is a normal IT ratio in newborns?
A: Typically >0.75 in healthy newborns with physiological jaundice. Ratios <0.5 may suggest significant conjugated hyperbilirubinemia.

Q2: When should IT ratio be measured?
A: When evaluating neonatal jaundice, especially if direct bilirubin is elevated or cholestasis is suspected.

Q3: Are there limitations to this ratio?
A: The ratio should be interpreted in clinical context as overlap exists between conditions. Some laboratories measure direct bilirubin and calculate indirect as total minus direct.

Q4: How does this help in NICU practice?
A: Helps differentiate hemolytic jaundice (high ratio) from biliary obstruction/low ratio), guiding further evaluation and management.

Q5: Does this replace fractionated bilirubin testing?
A: No, it's a screening tool. Formal fractionated bilirubin testing may be needed for precise diagnosis.