Bacterial Meningitis Score (BMS) Calculator
Enter CSF and clinical findings for a child to calculate the Bacterial Meningitis Score and assess risk for bacterial vs. aseptic meningitis.
Clinical Inputs
Patient age: 29 days – 19 years with CSF pleocytosis
CSF Gram Stain
CSF Absolute Neutrophil Count (ANC)
CSF Protein
Peripheral Blood ANC
Seizure at or before presentation
Select clinical findings and press
Calculate BMS Score
BMS Result
Bacterial Meningitis Score
0
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Clinical Interpretation
Score Breakdown
Total
This tool is for clinical decision support only. Always apply institutional protocols and physician judgment. Not validated for neonates under 29 days or immunocompromised patients.
Summary
Enter CSF and clinical findings for a child to calculate the Bacterial Meningitis Score and assess risk for bacterial vs. aseptic meningitis.
How it works
- Enter CSF findings: Gram stain result, absolute neutrophil count (ANC), and protein level.
- Enter the peripheral blood absolute neutrophil count from the CBC.
- Indicate whether the patient had a seizure at or before presentation.
- The tool sums the five criteria to produce a BMS score (0–6).
- A score of 0 indicates low risk (~0.1%) for bacterial meningitis; score ≥1 suggests empiric antibiotics are warranted.
Use cases
- Stratify bacterial vs. aseptic (viral) meningitis risk in febrile children with CSF pleocytosis.
- Support decision-making on empiric antibiotic therapy in the emergency department.
- Identify low-risk patients who may avoid unnecessary antibiotic exposure.
- Communicate risk to clinical teams and document clinical decision support rationale.
Frequently Asked Questions
Last updated: 2026-07-22 ·
Reviewed by Nham Vu