Why use it

Identifies surgical patients who need pharmacological thromboprophylaxis beyond mechanical compression alone. Evidence shows that high-risk patients (Caprini ≥ 5) benefit significantly from extended prophylaxis. Reduces preventable deaths from PE, the most common preventable cause of in-hospital death.

About

The Caprini Risk Assessment Model (RAM) is the most widely validated and used tool for estimating venous thromboembolism (VTE) risk in surgical patients. It assigns weighted points to over 30 individual risk factors across demographic, clinical, and surgical domains. The cumulative score places patients into one of four risk categories (Low, Moderate, High, Highest) that directly guide the type and duration of thromboprophylaxis. The 2005 updated Caprini model is endorsed by the American College of Chest Physicians (ACCP) and the American Society of Clinical Oncology (ASCO) guidelines.

When to use

Pre-operatively for all surgical patients to determine prophylaxis needs
General surgery, orthopedic, gynecological, urological, plastic/reconstructive, and bariatric surgery patients
Patients with multiple VTE risk factors being admitted for surgery
Determining duration of post-discharge thromboprophylaxis (extended prophylaxis)

Formula

Weighted points summed across risk factors: 1-point factors: Age 41–60, Minor surgery, BMI > 25, Swollen legs, Varicose veins, Pregnancy/postpartum, Oral contraceptives/HRT, Sepsis < 1 month, Serious lung disease, Abnormal pulmonary function, Acute MI, CHF, IBD, Medical patient at bedrest 2-point factors: Age 61–74, Arthroscopic surgery, Major open surgery >45 min, Laparoscopic surgery >45 min, Malignancy, Confined to bed > 72h, Immobilizing cast, Central venous access 3-point factors: Age ≥75, VTE history, Family history of VTE, Factor V Leiden, Prothrombin 20210A, Lupus anticoagulant, Anticardiolipin Ab, Elevated serum homocysteine, HIT, Other congenital or acquired thrombophilia 5-point factors: Stroke < 1 month, Elective major lower extremity arthroplasty, Hip/pelvis/leg fracture < 1 month, Acute spinal cord injury < 1 month, Multiple trauma < 1 month Total: 0 → ∞ Low: 0–1 | Moderate: 2 | High: 3–4 | Highest: ≥5

Pearls & pitfalls

A Caprini score ≥ 5 is associated with a 6–7% 30-day VTE rate without prophylaxis — highest risk category.
Malignancy adds 2 points; prior VTE adds 3 points — these are the most impactful individual factors.
Age is weighted progressively: age 41–60 = +1, 61–74 = +2, ≥75 = +3.
The model applies to adult surgical patients; separate tools (PADUA, IMPROVE) are used for medical inpatients.
Mechanical prophylaxis (sequential compression devices) should be used in all risk categories unless contraindicated.
Patients with bleeding risk: weigh VTE risk vs. bleeding risk individually; mechanical-only prophylaxis may be appropriate.
Extended prophylaxis for 28 days is recommended for major abdominal/pelvic cancer surgery (ACCP Grade 1B).

Next steps

Score 0–1 (Low): Early ambulation only; no pharmacologic prophylaxis needed. Score 2 (Moderate): Low-molecular-weight heparin (LMWH) or unfractionated heparin (UFH) + mechanical prophylaxis. Score 3–4 (High): LMWH or UFH + mechanical prophylaxis. Score ≥5 (Highest): Extended pharmacologic prophylaxis (28 days post-discharge for abdominal/pelvic cancer surgery); LMWH or UFH + mechanical prophylaxis in hospital.

Evidence

Caprini JA et al. (Am J Surg 1991; updated 2005). Validated in multiple large surgical cohorts. The 2005 model validated in >8,000 surgical patients. ACCP 9th edition endorses Caprini-based risk stratification for surgical VTE prophylaxis. AUC 0.73–0.82 across surgical populations.

References

Caprini JA. Thrombosis risk assessment as a guide to quality patient care. Dis Mon. 2005;51(2-3):70-78. — link
Gould MK et al. Prevention of VTE in nonorthopedic surgical patients: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: ACCP. Chest. 2012;141(2 Suppl):e227S-e277S. — link

Caprini Score for Venous Thromboembolism

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