The Pratt’s test assesses for deep vein thrombosis. The patient lies supine with their knee bent. The examiner uses both hands to hold the calf while pressing on the popliteal vein, located on the posterior aspect of the knee. If this movement elicits pain, then the test is positive for deep vein thrombosis.
Pratt GH (June 1949). “An early sign of femoral thrombosis”. J Am Med Assoc. 140 (5): 476. doi:10.1001/jama.1949.82900400001007. PMID 18129854.