Superficial vein thrombosis is an integral part of venous thromboembolism (VTE) together with deep vein thrombosis (DVT) and pulmonary embolism (PE). The incidence of SVT is 1.6 per 1000 persons per year. The incidence of DVT is about 1.0 per 1000 persons per year in the general population, 1.8 per 1000 persons per year at age 65 to 69 years and 3.1 per 1000 persons per year at age 85 to 89 years. First episodes of DVT are in two-thirds of cases elicited by risk factors, including varicose veins, cancer, pregnancy/ postpartum, oral contraceptives below the age of 50 years, immobility or surgery. Pain and tenderness in the calf and popliteal fossa may occur resulting from other conditions labeled as alternative diagnosis (AD) including Baker’s cyst, ruptured Baker’s cyst, torn plantaris tendon, hematoma, or muscle tears or pulls. The requirement for a safe diagnostic strategy of deep vein thrombosis (DVT) should be based on an objective post-test incidence of venous thromboembolism (VTE) of less than 0.1% with a negative predictive value for exclusion of DVT of 99.99% during 3 months follow-up. Modification of the Wells score by elimination of the “minus 2 points” for AD is mandatory and will improve clinical score assessment for DVT suspicion in the primary care and outpatient medical diagnostic setting. Compression ultrasonography (CUS) for proximal DVT overlooks distal DVT and is not cost-effective enough to rule in or out DVT. Complete CUS (CCUS) does pick up alternative diagnoses (AD) like Bakers cyst, muscle hematomas, old DVT, and superficial vein thrombosis (SVT). ADs with a negative CCUS include leg edema, varices erysipelas are easily picked up by physical examination. The sequential use of CCUS followed by quantitative rapid ELISA-D-dimer testing and modified Wells’ clinical score assessment is cost-effective and objective diagnostic algorithm that can safely and effectively exclude and diagnose both DVT and AD in patients with suspected DVT. About 10 to 30% of patients with DVT develop overt PTS (CEAP, C4,5) at one year post-DVT. DVT has a recurrence rate of about 20% to 30% after 5 years. A scoring system for lower extremity venous thrombosis (LET) extension on CCUS related to therapeutic implications is presented to prevent DVT recurrence and the post-thrombotic syndrome (PTS).