JAMA 1998 Apr 8;279(14):1094.
This systematic review of clinical assessment and tests for diagnosing DVTs found that leg swelling (as with other symptoms and signs, see Table 2) occurred in patients with and without DVTs. Presence of 1 or more of these signs (pain, tenderness, edema, Homans sign, swelling or erythema) did not have good positive or negative likelihood ratios for diagnosing or ruling out DVT (see Table 3 for LRs from various studies. Now various clinical prediction rules have been developed that combine clinical assessment with test results.

Phys Ther 2004 Aug;84(8):729. This review suggests physical therapists should screen for DVT using such a clinical decision rule and refer any patients with 3 points or more to physician immediately for possible further testing. Points based on the following:
Add 1 point each for
1. active cancer
2. paralysis, paresis or recent plaster immobilization of lower extremities
3. recent episode of being bedridden after major surgery
4. localized tenderness
5. leg swelling
6. calf swelling > 3 cm compared with asymptomatic leg
7. pitting edema
8. collateral superficial veins
Subtract 2 points if alternative diagnosis as or more likely than DVT. Limitations:  This review focused on outpatients.

Reviewed 4/21/2014 ldt