The Caprini Risk Assessment Model (Joseph Caprini, 2005) is the most widely-validated VTE risk score for surgical and hospitalised medical patients. It scores 40+ risk factors weighted 1, 2, 3, or 5 points based on relative risk. A 2010 validation in 8,216 patients showed a 14-fold increase in 30-day VTE between Caprini ≤1 and Caprini ≥8.

It is endorsed by the American College of Chest Physicians (ACCP), American College of Surgeons (NSQIP), and is the de-facto risk-assessment tool in NABH-accredited Indian hospitals.

• 0 points (Very Low): Early ambulation. No prophylaxis.
• 1–2 (Low): Mechanical prophylaxis (IPC or graduated stockings).
• 3–4 (Moderate): LMWH (enoxaparin 40 mg SC OD) OR UFH 5000 U SC TDS, 7–10 days.
• ≥5 (High): LMWH + mechanical. For major arthroplasty / hip-fracture surgery: extend 28–35 days. For active-cancer surgery: extend 4 weeks.

• Enoxaparin (Clexane, Lonox) — 40 mg SC OD for prophylaxis (~₹150–250/day). Reduce to 30 mg SC OD if CrCl 15–30. Avoid if CrCl <15.
• Dalteparin (Fragmin) — 5000 U SC OD.
• Unfractionated heparin — 5000 U SC TDS (~₹30/day). Use when CrCl <15 or cost-constrained.
• Fondaparinux (Arixtra) — 2.5 mg SC OD; preferred if HIT history.
• DOACs for orthopaedic prophylaxis — rivaroxaban 10 mg OD (₹50–80/day) or apixaban 2.5 mg BD; widely used after THR/TKR in India.

• Active major bleeding or high bleeding risk (IMPROVE bleeding score ≥7)
• Platelet count <50,000 or INR >1.5 unrelated to anticoagulation
• Recent intracranial haemorrhage / neurosurgery (within 14 days)
• Severe uncontrolled hypertension
• HIT in last 100 days — switch to fondaparinux / DOAC
• Epidural catheter in situ — time LMWH 12h pre / 4h post-removal

In these cases use IPC alone and reassess every 24h.