Neonatal Bilirubin Calculator

Check bilirubin level against newborn age in hours. Add gestation, weight, and risk factors quickly. Get clear categories and next-step suggestions for clinicians today.

Input form
Enter newborn details
Fields marked are required.
Conversion used: 1 mg/dL = 17.1 µmol/L.
Optional trend
What this adds
  • Calculates rate-of-rise (mg/dL/hr).
  • Flags rapid increases for closer review.
  • Supports planning for repeat testing.
Risk factors (tick if present)
Clinical note
Use this tool for screening support only. Always confirm with local guidelines and senior review, especially for early jaundice.
Reset
Example data table
Case Age (h) TSB (mg/dL) Gestation (w) Risk factor(s) Example output
A 24 9.5 39 None Moderate zone, routine follow-up
B 36 13.2 37 GA < 38 weeks Near phototherapy level, close follow-up
C 48 16.1 40 Bruising Phototherapy level reached
D 60 22.0 39 Hemolysis suspected Urgent evaluation threshold reached

Examples are illustrative and may not match your protocol.

Formula used
How to use this calculator
  1. Enter age in hours and the measured bilirubin value.
  2. Select the unit and add gestation and weight.
  3. Tick relevant risk factors if present.
  4. Optionally enter a previous bilirubin and time gap.
  5. Click Calculate to view results above the form.
  6. Download a CSV or PDF report for documentation.

Age in hours anchors interpretation

Newborn bilirubin changes fast, so age in hours matters more than calendar days. The calculator asks for hours since birth and compares the result to age-specific reference knots from 0 to 168 hours. Linear interpolation estimates a threshold at the exact hour you enter, avoiding abrupt jumps between day-based tables. Physiologic jaundice often peaks around 72–120 hours, so early-hour context is critical.

Unit conversion keeps reports consistent

Hospitals may report total serum bilirubin (TSB) in mg/dL or µmol/L. The tool converts values using 1 mg/dL = 17.1 µmol/L, then performs comparisons in mg/dL. Displaying both units helps when referrals arrive with different lab formats and supports handover communication. Always document whether the value is serum or transcutaneous.

Risk tier adjusts caution levels

Thresholds are tighter when vulnerability is higher. Gestation below 38 weeks and major factors such as suspected hemolysis, G6PD deficiency, or sepsis are grouped as High tier. Minor factors like bruising or poor intake form Medium tier. The calculator applies an illustrative downward shift to the phototherapy threshold for these tiers to represent earlier action in many protocols. Add weight loss and hydration assessment alongside this tiering.

Trend entry highlights rapid rise

If you enter a previous TSB and the hours between samples, the tool calculates rate of rise: (TSBnow − TSBprev) ÷ hours. A rising trend near a threshold can justify earlier repeat testing, feeding support, and senior review. A stable or falling trend supports routine surveillance when other risks are absent. Rapid rises are particularly concerning in the first 24–48 hours.

Graph supports bedside explanation

The Plotly chart overlays two curves: a phototherapy reference and a higher exchange-evaluation reference. Your point is plotted at the entered age, making it easier to explain why a value is considered “below,” “near,” or “at” a threshold. This visual framing can improve shared decisions about timing of repeat blood tests. The curve snapshot table lists knot thresholds for verification.

Outputs fit documentation workflows

Results include the interpreted status, thresholds at the current age, and a follow-up suggestion. Use CSV for logs and PDF for transfer notes. The calculator is a decision-support aid only; always apply local guidance and escalation pathways.

FAQs

1) Is this a replacement for an approved nomogram?

No. It is a structured helper with illustrative thresholds. Always use your institution’s guideline and clinical judgment for diagnosis, treatment, and escalation decisions.

2) Which bilirubin measurement should I enter?

Enter the current total serum bilirubin if available. If you have a transcutaneous value, follow local rules for when a confirmatory serum test is required, especially near thresholds.

3) Why does gestational age change the category?

Lower gestational age is associated with higher susceptibility to bilirubin-related complications. Many protocols recommend earlier intervention or closer follow-up for newborns below 38 weeks.

4) What does “rate of rise” mean here?

It is the change in bilirubin divided by the time between two measurements. A faster rise can indicate higher risk and may justify earlier repeat testing and senior review, depending on your protocol.

5) Can I use this after the first week?

This page focuses on early newborn monitoring (0–168 hours). Persistent jaundice after the first week often needs a different evaluation pathway for prolonged jaundice causes.

6) Do the downloads contain personal identifiers?

No. The exports include only the numerical inputs and computed outputs shown on the page. Keep patient identifiers out of this tool and document officially in your clinical record system.

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Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.