How this calculator works
This is the original eight-variable Haukoos model, not the refined version. Sexual-practice and other-risk entries are independent and can apply together. Race/ethnicity reproduces a historical statistical association in the study populations; it does not imply a biological cause. The score is a historical screening tool and must not be used to rule out infection, defer testing or determine post-exposure care. The result is an estimate for information only and is not medical advice.
Formula
Add the published points: age <22 or >60: 0; 22-25 or 55-60: 4; 26-32 or 47-54: 10; 33-46: 12. Male: 21; Black: 9; Hispanic: 3; other reference groups: 0. Sex with a male: 22; vaginal intercourse: -10; receptive anal intercourse: 8; injection drug use: 9; past test: -4.
Worked example
A 30-year-old woman in the reference race category with vaginal intercourse and a past HIV test scores 10 - 10 - 4 = -4. A 40-year-old Black man reporting sex with a male, receptive anal intercourse and injection drug use scores 81.
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Frequently asked questions
Why are behaviours separate?
The original model adds all applicable terms. Selecting only the highest-scoring behaviour would change the published score.
What do the strata mean?
The paper groups scores as <20, 20-29, 30-39, 40-49 and at least 50. They describe study strata, not an individual probability.
Can a low score exclude HIV?
No. Testing is needed to establish HIV status, and a low score does not remove the need for assessment after an exposure.