How to know if you have a pulmonary embolism? i think i have a calf sprain. what's the major differences and sign you need to see a dr.

Tachycardia &: Hypoxia are 2 greatest signs of pulmonary embolism.

Positive Chest CT: If you present with possible signs of pe (shortness of breath, rapid pulse, chest pain, etc) a ct scan of the chest with contrast will frequently be done to confirm the diagnosis of pe. Then you would know. A calf "sprain" could be clots in the leg veins but only infrequently progress to a pe.