What does a positive tb test look like? – A tuberculin reaction is classified as positive based on the diameter of the induration in conjunction with certain patient-specific risk factors. In a healthy person whose immune system is normal, induration greater than or equal to 15 mm is considered a positive skin test. If blisters are present (vesiculation), the test is also considered positive. This video is showing how does positive tb test look like.
This pictures is showing how does positive tb test look like.