Functional limitation in ankylosing spondylitis. Free to use.
BASFI (Bath Ankylosing Spondylitis Functional Index) is a validated clinical instrument used to assess functional limitation in ankylosing spondylitis. The instrument contains 10 items.
Source / attribution: Calin A et al. J Rheumatol. 1994;21(12):2281-2285.
The instrument's primary construct — functional limitation in ankylosing spondylitis — is operationalized through a fixed set of items, each with a defined response format. This standardisation is what allows BASFI scores to be compared meaningfully across clinicians, sites, and studies.
Like all screening or assessment instruments, BASFI is a structured aid — not a diagnostic test in isolation. Results should be interpreted alongside history, examination, and clinical context. Where a score crosses an actionable threshold, the next step is typically a more detailed clinical evaluation rather than a definitive diagnosis.
Answer all 10 items below to see your BASFI score and interpretation.
All scoring runs in your browser. No data is sent anywhere — close the tab and the answers are gone.
BASFI uses a published formula (basfi) rather than simple summation. The formula and its inputs are visible in our open-source scoring engine.
Scoring notes: BASFI = mean of 10 items, each scored 0 (easy) – 10 (impossible). Range 0–10.
The cutoffs below are drawn from the published validation literature. Always interpret in clinical context.
| Score range | Band | Interpretation |
|---|---|---|
| 0–2.5 | Minimal limitation | Functional impact is small. |
| 2.6–5 | Mild limitation | Mild functional restriction. |
| 5.1–7.5 | Moderate limitation | Significant functional restriction. |
| 7.6–10 | Severe limitation | Major functional impairment; comprehensive care indicated. |
BASFI uses a published formula rather than simple summation. Below is a step-by-step calculation with illustrative inputs.
| Input | Value |
|---|---|
| Q1 | each = 5 |
| Q2 | each = 5 |
| Q3 | each = 5 |
| Q4 | each = 5 |
| Q5 | each = 5 |
| Q6 | each = 5 |
| Q7 | each = 5 |
| Q8 | each = 5 |
| Q9 | each = 5 |
| Q10 | each = 5 |
Score = 5 → Mild limitation
If BASFI doesn't fit your context, related instruments in rheumatology include:
| Scale | Measures | Items | Time |
|---|---|---|---|
| BASDAI | Disease activity in ankylosing spondylitis | 6 | — |
| ODI | Self-reported low-back-pain functional disability | 10 | — |
| NDI | Self-reported neck-pain functional disability | 10 | — |
| LEFS | Function with lower-extremity musculoskeletal disorders | 20 | — |
| Oxford Knee Score | Pain and function after total knee replacement | 12 | — |
| Oxford Hip Score | Pain and function after total hip replacement | 12 | — |
| IPSS | Lower-urinary-tract symptoms in men | 7 | — |
| IIEF-5 / SHIM | Erectile dysfunction screen | 5 | — |
BASFI (Bath Ankylosing Spondylitis Functional Index) is a validated instrument that assesses functional limitation in ankylosing spondylitis. It is designed for clinicians, medical students, evidence-synthesis researchers. The 10 items are combined to produce a total score.
BASFI contains 10 items. Items feed into a scoring formula that produces the total. Scores run from 0 to 10, grouped into 4 interpretation bands from ‘Minimal limitation’ up to ‘Severe limitation’.
On the BASFI (total score 0–10), scores of 7.6–10 fall in the ‘Severe limitation’ band — interpreted as: Major functional impairment; comprehensive care indicated. The full ladder is: 0–2.5 — Minimal limitation: Functional impact is small.; 2.6–5 — Mild limitation: Mild functional restriction.; 5.1–7.5 — Moderate limitation: Significant functional restriction.; 7.6–10 — Severe limitation: Major functional impairment; comprehensive care indicated. A higher score reflects a more severe presentation, and crossing a cutoff is a prompt to step up assessment or care — but these bands are screening thresholds, not diagnoses.
Scores of 0–2.5 fall in the ‘Minimal limitation’ band: Functional impact is small. A low score is reassuring but does not by itself rule out the underlying condition — if symptoms or clinical suspicion persist, reassess over time or use a complementary evaluation rather than relying on the number alone.
Yes — BASFI is in the public domain and free for clinical, educational, and research use without permission. You can use this calculator and the scale itself freely; if you publish results or reproduce the scale, cite the original source paper.
Calin A et al. A new approach to defining functional ability in ankylosing spondylitis. J Rheumatol. 1994;21(12):2281-2285. This is the original publication for the BASFI — the reference to cite when reporting results.
No. BASFI is a structured assessment aid, not a diagnostic test. Its proper role is clinical assessment of functional limitation in ankylosing spondylitis — it standardizes assessment and flags who needs closer evaluation, but the result must be weighed alongside history, examination, and clinical context. When a score conflicts with your clinical impression, clinical judgment takes precedence; treatment decisions should never rest on a screening score alone.
BASFI is supported by the following peer-reviewed sources: