Signs of a possible blood clot in a leg or arm may include new swelling, pain, tenderness, warmth, or a change in skin color. A clot affecting the lungs may cause trouble breathing, chest pain, coughing, a fast heartbeat, lightheadedness, or fainting.1
These symptoms require immediate care. If you have sudden trouble breathing, chest pain, coughing up blood, fainting, or severe or worsening symptoms, seek medical help right away instead of taking this test or waiting to receive your results.1,2