Common Symptoms Table 2–6.

Table 2–6. Risk stratification of adults referred for ultrasound to rule out DVT.

                                 Step 1: Calculate risk factor score
Score 1 point for each
Untreated malignancy
Paralysis, paresis, or recent plaster immobilization
Recently bedridden for > 3 days due to major surgery within 4 weeks
Localized tenderness along distribution of deep venous system
Entire leg swelling
Swelling of one calf > 3 cm more than the other (measured 10 cm below tibial tuberosity)
Ipsilateral pitting edema
Collateral superficial (nonvaricose) veins
Previously documented DVT

Alternative diagnosis as likely as or more likely than DVT: subtract 2 points

                                        Step 2: Obtain ultrasound
Score                     Ultrasound Positive                    Ultrasound Negative
≤ 0                         Confirm with venogram                DVT ruled out
1–2                          Treat for DVT                             Repeat ultrasound in 3–7 days
≥ 3                           Treat for DVT                             Confirm with venogra

• DVT, deep venous thrombosis.