Symptom-based probability scoring for healthcare workers. Not a diagnostic device — for clinical decision support only.
⚠ Important safety information — read before use
This tool does not diagnose Lassa fever. It provides probability estimates to support clinical decision-making. All results require laboratory RT-PCR confirmation. Probability estimates are based on published clinical literature and must not replace clinical judgment.
Report any suspected case to NCDC immediately — do not wait for laboratory results before notifying.
Section 2 — Major symptoms (higher specificity for Lassa fever)
Section 3 — Other symptoms
Section 4 — Exposure history (last 21 days)
Probability estimate
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Probability estimate based on symptom weights derived from published Lassa fever clinical literature (McCormick 1987, Okokhere et al. 2018, Brosh-Nissimov 2020). All results require laboratory RT-PCR confirmation. This is not a diagnostic result.
Risk category and recommended action
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Differential — conditions to consider
Relative likelihoods in a febrile patient presenting in Nigeria. These are illustrative estimates to support the workup, not validated diagnostic probabilities. Lassa fever co-infection with malaria is common and does not exclude either condition.
Recommended clinical actions
☐Place patient in single-room isolation
☐Use full PPE: gloves, gown, N95/FFP2 mask, eye protection
☐Collect blood sample for Lassa RT-PCR (contact NCDC for nearest lab)
☐Notify state epidemiologist now
☐Report to NCDC: 0800-970000-10
☐Document full exposure history and potential contact list
☐If RT-PCR will be delayed more than 24 hours and clinical suspicion remains very high: consider empirical ribavirin after discussion with senior clinician and NCDC — do not administer without senior clinical oversight.
Medical disclaimer. This tool provides probability estimates only and does not constitute a medical diagnosis, clinical advice, or a recommendation for treatment. Probability estimates are derived from published clinical scoring literature for Lassa fever and have not been prospectively validated in a clinical study. All clinical decisions must be made by qualified healthcare professionals. This tool is intended to support, not replace, clinical judgment. GaiaLab accepts no liability for clinical decisions made using this tool.
Data privacy. No symptom data entered in this form is transmitted to any server. All calculations run entirely in your browser. Nothing is stored or logged.