What is calculated
The original age-and-weight OSTA screening index.
OSTA Osteoporosis Screening Calculator
OSTA index
Enter your values, then calculate to see a verified result.
Reference range
How this result is calculated
A clear calculation path based on your inputs.
Inputs usedReview the information used for this result.
Full calculation and sourcesOpen Full calculation and sources to review the method, assumptions, boundaries, and evidence.
Versioned calculationFormula v1.0.0
Method
Subtract age from weight in kilograms and multiply by 0.2.
Important boundary
Population fit, age-dependent performance, fracture history, medicines, and DXA are not modeled.
Enter age and weightUse the labeled field and matching unit.
Apply the OSTA equationThe calculator applies the displayed method at full precision.
Confirm with appropriate assessmentKeep the stated boundary beside the result.
Interpretation
The primary value is the published screening index.
Age and weight remain visible beside it.
A band is not a diagnosis or fracture probability.
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Related calculators and resources
Method and test recordFormula v1.0.0
- Recorded scope
- health-evidence-completion
- Publisher
- CalculatorGeek
- Recorded review date
- 2026-10-05
- Next source review
- 2027-04-05
- Definition fixtures
- 2 configured scenarios
- Published examples
- 2 shown below
Recorded method
Verify raw OSTA arithmetic, metric/imperial parity, exact -4/-1 band behavior, and source-population wording.
These records describe the published model and reference tests. A test-case count is not a certification of every possible input or an independent specialist review. Editorial policy
Known limitations
- Original validation focused on postmenopausal Asian women.
- Does not include prior fracture, steroid exposure, menopause history, smoking, alcohol, or DXA.
- Threshold performance can vary by age and population.
- Not a fracture-probability model.
Method sources
Latest model update
2026-10-05 - Initial evidence-limited shared-system implementation with fixtures, original support content, and contextual links.
Reference inputs and expected results
Up to 12 examples from the configured definition fixtures are shown. Expected values use the stated output units; invalid inputs are intended to be rejected.
| Case | Inputs | Expected result |
|---|---|---|
| intermediate source band | Age: 65 years; Body weight: 55 kg | OSTA index: -2 points; classification: intermediate-risk-band (allowed numeric tolerance: 0.0001) |
| low boundary | Age: 60 years; Body weight: 56 kg | OSTA index: -0.8 points; classification: low-risk-band (allowed numeric tolerance: 0.0001) |
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On this page
What the OSTA Osteoporosis Screening Calculator calculates
Calculate the Osteoporosis Self-assessment Tool for Asians (OSTA) index from age and weight.
The source population is kept in the page name and limitations rather than generalized to everyone.
Start with the Health calculators hub when a neighboring workflow better matches the question.
How to use the OSTA Osteoporosis Screening Calculator
- Enter age in years.
- Enter measured weight.
- Read the raw index and source-specific band.
- Use appropriate local screening guidance and clinical assessment.
Continue with the Body Surface Area Calculator. Keep size-normalization arithmetic separate.
Formula, variables and calculation order
OSTA = 0.2 x (weight kg - age years).
Inputs are validated and normalized before the calculation. Working precision is retained until display rounding.
For a separate method, open the BMI Calculator. Review adult weight-for-height screening.
Worked example and boundary check
Worked example
Age 65 and weight 55 kg gives -2.0, the intermediate source band.
Boundary check
An index of -1 is intermediate under the displayed boundaries; a value greater than -1 is low.
How to interpret the result
Use the result only as a source-specific screening prompt, not proof of low bone density.
- Original validation focused on postmenopausal Asian women.
- Does not include prior fracture, steroid exposure, menopause history, smoking, alcohol, or DXA.
- Threshold performance can vary by age and population.
- Not a fracture-probability model.
Compare the result with the Vitamin D Reference Calculator. Compare intake with cited reference values.
Frequently asked questions
Is OSTA the same as FRAX?
No.
Does a high band diagnose osteoporosis?
No.
Why only age and weight?
That is the deliberately simple original screening model.
Can men use this band?
The original validation does not justify assuming equivalent performance.
Primary sources and evidence limits
Sources and version-sensitive boundaries were checked 2026-10-05. The page does not replace diagnosis, prescribing, emergency care, or individualized professional judgment.