Clinical calculator
Caprini Calculator
Caprini Risk Assessment Model for venous thromboembolism
The Caprini Risk Assessment Model estimates the risk of venous thromboembolism in a surgical patient by adding risk factors weighted 1, 2, 3 or 5 points — with elective lower limb arthroplasty, a hip, pelvis or leg fracture, stroke and acute spinal cord injury each worth 5 — to give a total that hospital protocols then map to a prophylaxis level.
What the Caprini score means
Caprini totals run from 0 to 84, where a lower score is better. No severity bands are shown because no cut-offs have been published that we can verify — read the total against the source studies and your own protocol, as described below.
How the score is calculated
Stated in full so the calculation can be independently checked, and reproduced by hand if needed.
Each risk factor that is present contributes its weight and the weights are added. Age contributes 1 point at 41 to 60 years, 2 points at 61 to 74 and 3 points at 75 or over. One point each: minor surgery planned, prior major surgery within a month, varicose veins, inflammatory bowel disease, current swollen legs, BMI over 25, acute myocardial infarction, congestive heart failure within a month, sepsis within a month, serious lung disease including pneumonia within a month, abnormal pulmonary function, and a medical patient at bed rest; and, for women, oral contraceptives or hormone replacement, pregnancy or the first month postpartum, and a history of unexplained stillbirth, recurrent miscarriage, premature birth with toxaemia or a growth-restricted infant. Two points each: arthroscopic surgery, malignancy, major open surgery over 45 minutes, laparoscopic surgery over 45 minutes, confinement to bed over 72 hours, an immobilising plaster cast within a month, and central venous access. Three points each: a history of DVT or pulmonary embolism, a family history of thrombosis, factor V Leiden, prothrombin 20210A, raised homocysteine, lupus anticoagulant, anticardiolipin antibodies, heparin-induced thrombocytopenia and other thrombophilia. Five points each: elective major lower extremity arthroplasty, hip, pelvis or leg fracture within a month, stroke within a month, multiple trauma within a month, and acute spinal cord injury with paralysis within a month. A higher total means more recorded risk factors for venous thromboembolism. The original form also leaves room for other risk factors, which are not included here. No risk levels are shown because the groupings differ between versions and institutions.
Missing data
A risk factor left unmarked is counted as absent, which is how the model is used in practice — it is a checklist, not a questionnaire with a missing-value rule. An incompletely marked form returns a total that can only be an underestimate, and the result says so.
Instrument profile
- Developer
- Joseph A. Caprini
- Institution
- NorthShore University HealthSystem, United States
- First published
- 2005
- Custodian
- Joseph A. Caprini
- Items
- 37
- Response format
- Age in years plus present or absent for each of 36 risk factors
- Score range
- 0 to 84
- Direction
- Lower score = better
- Recall period
- Current status at the time of assessment; several factors apply only within one month of the event
- Completion time
- About 4 minutes
- Age range
- Adults
- Regions
- General Health
- Conditions
- Venous thromboembolism, Deep vein thrombosis, Pulmonary embolism, Perioperative risk
- Procedures
- Total hip arthroplasty, Total knee arthroplasty, Hip fracture surgery, Spinal surgery, Arthroscopic surgery
- Languages
- English
- Validity
- The weights were assigned from the published thrombosis literature and clinical experience rather than fitted statistically to a single patient cohort, and the model has since been tested retrospectively in surgical cohorts. Its factors, weights and groupings have been revised, so validity data apply to the version that was tested.
- Reliability
- Not applicable: it describes risk at a point in time and is reassessed rather than tracked.
When to use the Caprini
Well suited to
- Recording the number and weight of venous thromboembolism risk factors in a surgical patient so that a hospital protocol can assign prophylaxis.
- Understanding how an arthroplasty or fracture patient reaches a high total — lower limb arthroplasty and a hip, pelvis or leg fracture are each worth 5 points before any other factor is counted.
Limitations and poor fits
- Deciding on prophylaxis from the total alone. The model does not say what to do about a score; the local protocol and the bleeding risk do.
- Diagnosing deep vein thrombosis — use a pre-test probability rule such as the Wells score for that.
- Comparing totals between versions of the model, which differ in factors and weights.
- Any decision that needs a calibrated risk estimate for an individual patient: the weights were assigned from the literature and clinical experience, not fitted to outcome data.
Caprini compared with other instruments
Instruments measuring a related construct, with the practical difference between them.
| Instrument | Items | Range | What it adds |
|---|---|---|---|
| Wells DVT | 10 | -2–9 | The Wells score for deep vein thrombosis estimates pre-test probability from ten clinical criteria, nine of which add a point and one of which subtracts two, stratifying patients into low, moderate and high probability groups that carry roughly 5%, 17% and 53% prevalence of DVT. |
| ASA | 2 | 1–6 | The ASA Physical Status Classification grades a patient’s pre-operative systemic health from I, a normal healthy patient, to VI, a declared brain-dead organ donor, with an E modifier added for emergency procedures. |
| CCI | 17 | 0–37 | The Charlson Comorbidity Index is a weighted checklist of 16 comorbid conditions that produces a comorbidity score of 0 to 33, to which up to 4 points are added for age, and which estimates 10-year survival at roughly 98% for a total of 0, 90% for 2, 53% for 4 and 21% for 5. |
| Elixhauser | 21 | -19–89 | The Elixhauser comorbidity score applies the van Walraven point weights to 30 comorbidities, giving each a whole-number weight from −7 to +12 so that their sum predicts in-hospital death from hospital diagnosis codes — and in one large national inpatient dataset it discriminated slightly better than the Charlson index. |
Copyright and permitted use
Published openly because it is the question every clinician and researcher asks before using an instrument, and almost nobody answers it.
The model is reproduced in professional-society and hospital materials, and the copy we worked from is marked as reprinted with the author’s permission, so we cannot treat it as free of copyright. We have not approached the author. If the rights holder objects, the item wording will be removed and the page reduced to a profile.
References
- Caprini JA. Thrombosis risk assessment as a guide to quality patient care. Disease-a-Month. 2005.
- Bahl V, Hu HM, Henke PK, Wakefield TW, Campbell DA Jr, Caprini JA. A validation study of a retrospective venous thromboembolism risk scoring method. Annals of Surgery. 2010.
Editorial status
This page has not yet been signed off by a named clinical reviewer. The scoring logic is stated in full above so it can be independently verified, and every threshold is traceable to its source. See our editorial methodology.