Variables of the Oudega rule.
| Variable | Points | Regression coefficienta |
|---|---|---|
| Male sex | 1 | 0.59 |
| Oral contraceptive use | 1 | 0.75 |
| Presence of active malignancy (within last 6 months) | 1 | 0.42 |
| Major surgery (last 3 months) | 1 | 0.38 |
| Absence of leg trauma | 1 | 0.60 |
| Vein distension | 1 | 0.48 |
| Calf swelling ≥3cm | 2 | 1.13 |
| Abnormal D-dimer result | 6 | 3.01 |
The score could range from 0 to 14: ≤3 = not referred for compression ultrasonography, ≥4 = directly referred for compression ultrasonography.
↵a The score was derived from the following original logistic model: probability DVT = 1/(1+exp (-5.47+0.59*male sex + 0.75*oral contraceptive use + 0.42*presence of active malignancy + 0.38*major surgery + 0.60*absence of leg trauma + 0.48*vein distension + 1.13*calf swelling ≥3 cm + 3.01*abnormal D-dimer result). DVT= deep venous thrombosis.