In the Wells clinical prediction rule for suspected lower limb deep vein thrombosis, which single criterion carries a NEGATIVE point value?
- A An alternative diagnosis considered at least as likely as deep vein thrombosis ✓
- B Calf circumference more than 3 cm larger than the other leg
- C Active cancer treated within the last six months
- D Recently bedridden for more than three days or major surgery within 12 weeks
Correct answer: A. An alternative diagnosis considered at least as likely as deep vein thrombosis
Explanation
The Wells rule scores nine features, eight of which add one point each, including cancer, immobility, calf swelling over 3 cm and tenderness along the deep venous system. Only one entry subtracts points: if another diagnosis such as muscle tear or cellulitis is judged at least as probable as venous thrombosis, two points are deducted. This makes the rule sensitive but operator dependent, and a total score of two or more classifies the patient as likely enough to proceed straight to ultrasonography.
Reference: Kumar and Clark's Clinical Medicine, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.