Calculator Inputs
Enter clinical details first. Laboratory fields are optional and update the estimate when available.
Formula Used
This page uses a transparent educational point system so each contribution is visible.
Clinical Score = Age under 12 months × 2 + Temperature at least 39°C × 2 + History of UTI × 2 + Female or uncircumcised male × 2 + No other fever source × 2 + Fever at least 48 hours × 1
Laboratory Score = Nitrite positive × 5 + Leukocyte esterase weight + WBC band weight + Gram stain bacteria × 4
Total Score = Clinical Score + Laboratory Score
Estimated Risk = 100 ÷ (1 + e-((Total Score − Center) ÷ Spread))
Leukocyte esterase weights
- None = 0
- Trace = 1
- 1+ = 2
- 2+ = 3
- 3+ = 4
WBC per mm³ weights
- Below 10 = 0
- 10 to 49 = 2
- 50 to 99 = 3
- 100 or more = 4
How to Use This Calculator
- Enter the child’s age, highest temperature, sex, fever duration, prior UTI history, and whether another fever source is present.
- Add optional urine findings when available to refine the estimate.
- Press Calculate Risk Score to show the result below the header and above the form.
- Review clinical score, updated estimate, triggered factors, and the graph.
- Download the summary as CSV or PDF for documentation.
- Use the result as a screening aid only and follow professional medical evaluation for testing or treatment decisions.
Example Data Table
These examples are generated by the same educational model used in this file.
| Case | Profile | Clinical Score | Lab Score | Estimated Risk | Band |
|---|---|---|---|---|---|
| Example 1 | 6-month-old female | 9 | 15 | 99.5% | High |
| Example 2 | 18-month-old circumcised male | 0 | 1 | 1.6% | Very Low |
| Example 3 | 14-month-old uncircumcised male | 9 | 9 | 97.4% | High |
Frequently Asked Questions
1. What does this calculator estimate?
It estimates a screening-level likelihood of pediatric urinary tract infection from entered symptoms and optional urine findings. It helps organize risk factors, but it does not diagnose infection or replace a clinician’s judgment, urine culture, or urgent care when a child looks ill.
2. Can I use this for every child with fever?
Use caution outside the young-child fever context. The page is most useful when UTI is part of the differential diagnosis. Older children, toilet-trained children, and children without fever may need different clinical reasoning and different testing pathways.
3. Why are lab fields optional?
Many assessments begin before urine results are available. The calculator first estimates risk from symptoms and history, then updates the estimate when nitrite, leukocyte esterase, WBC count, or Gram stain information is entered.
4. Does a high result confirm a UTI?
No. A high result means the entered pattern deserves prompt clinical attention and usually formal testing. Confirmation still depends on proper urine collection, urinalysis interpretation, and culture results reviewed by a qualified clinician.
5. Why does sex or circumcision status affect the score?
Those factors are commonly considered in pediatric UTI screening because baseline risk differs across groups. This page uses them only to build an educational screening score, not to make a stand-alone treatment decision.
6. What should I do with a borderline result?
Borderline results mean context matters. Persistent fever, poor intake, vomiting, irritability, no clear alternate source, or clinician concern can justify urine testing even when the estimate is not high.
7. Can this replace a pediatrician or emergency evaluation?
No. Infants with lethargy, breathing trouble, dehydration, persistent vomiting, reduced responsiveness, seizures, or worsening fever need urgent medical assessment regardless of calculator output.
8. Why are CSV and PDF downloads included?
They make documentation easier. You can save the current inputs, scores, and recommendation for teaching, chart prep, handoff notes, or discussion with a supervising clinician or parent.