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Wells Score for DVT Calculator

Sums the Wells clinical criteria for suspected deep vein thrombosis and reports the three-tier (low/moderate/high) and two-tier (unlikely/likely) pretest probability categories.

Active cancer (treatment within 6 months or palliative) (optional)+1 point. Paralysis, paresis or recent plaster immobilisation of a leg (optional)+1 point. Bedridden >3 days or major surgery within 12 weeks (optional)+1 point. Localised tenderness along the deep venous system (optional)+1 point. Entire leg swollen (optional)+1 point. Calf swelling >3 cm vs the other leg (10 cm below tibial tuberosity) (optional)+1 point. Pitting oedema confined to the symptomatic leg (optional)+1 point. Collateral (non-varicose) superficial veins (optional)+1 point. Previously documented DVT (optional)+1 point (added in the 2003 modification). Alternative diagnosis at least as likely as DVT (optional)−2 points.

When to use

You are structuring the pretest probability of a first lower-limb DVT before D-dimer testing or ultrasound.

Do not use when: Suspected pulmonary embolism (the Wells PE score differs), pregnancy, or upper-limb DVT, where the score was not validated.

Formula

score = Σ positive criteria (1 point each) − 2 if an alternative diagnosis is at least as likely; low ≤ 0, moderate 1–2, high ≥ 3; unlikely ≤ 1, likely ≥ 2

Prevalence figures come from the 1997 derivation cohort; in the 2003 two-tier study a low score with a negative D-dimer safely excluded DVT without ultrasound. Results are informational only and not a substitute for clinical judgement or medical advice.

Inputs

Parameter	Type	Required	Description
`active_cancer`	boolean	default false	+1 point.
`paralysis_or_immobilisation`	boolean	default false	+1 point.
`bedridden_or_major_surgery`	boolean	default false	+1 point.
`localised_tenderness`	boolean	default false	+1 point.
`entire_leg_swollen`	boolean	default false	+1 point.
`calf_swelling_over_3cm`	boolean	default false	+1 point.
`pitting_oedema`	boolean	default false	+1 point.
`collateral_superficial_veins`	boolean	default false	+1 point.
`previous_dvt`	boolean	default false	+1 point (added in the 2003 modification).
`alternative_diagnosis_likely`	boolean	default false	−2 points.

Outputs

Output	Type	Description
`score`	integer	Sum of the criteria (−2 to 9).
`three_tier_probability`	string	Low (≤0, about 3% DVT prevalence), moderate (1–2, about 17%) or high (≥3, about 75%).
`two_tier_category`	string	DVT unlikely (≤1) or DVT likely (≥2).
`criteria_met`	string_list	Criteria that contributed to the score.

Example

Active cancer, calf swelling, localised tenderness: {"active_cancer":true,"calf_swelling_over_3cm":true,"localised_tenderness":true} → {"score":3,"three_tier_probability":"High (score ≥3; about 75% DVT prevalence)","two_tier_category":"DVT likely (score ≥2)"}

Entire leg swollen, alternative diagnosis likely: {"entire_leg_swollen":true,"alternative_diagnosis_likely":true} → {"score":-1,"three_tier_probability":"Low (score ≤0; about 3% DVT prevalence)","two_tier_category":"DVT unlikely (score ≤1)"}

GET https://tttkmbb.com/api/v1/calculate/wells-score-dvt?active_cancer=true&calf_swelling_over_3cm=true&localised_tenderness=true

Machine access

API: GET https://tttkmbb.com/api/v1/calculate/wells-score-dvt (query parameters) or POST with a JSON body {"inputs": {...}}
Schema: https://tttkmbb.com/api/v1/calculators/wells-score-dvt · Markdown: https://tttkmbb.com/medical/wells-score-dvt.md · JSON definition: https://tttkmbb.com/medical/wells-score-dvt.json
MCP: server https://tttkmbb.com/mcp, tool run_calculator with calculator_id="wells-score-dvt"
OpenAPI operationId: calculate_wells_dvt_score
Freshness: static. Authentication: none. Rate limit: fair use (see rate limits).

Sources

FAQ

What do I do with the category?

In the validated pathway, 'unlikely' plus a negative D-dimer excludes DVT; 'likely' or a positive D-dimer proceeds to compression ultrasound.

Which version is this?

The 2003 modified criteria (including previously documented DVT); the three-tier output uses the 1997 cut-offs, so both categorisations are shown.

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