What is tb skin test bruise?

A TB (tuberculosis) skin test typically involves injecting a small amount of liquid called tuberculin into the skin of the forearm. After 48 to 72 hours, the area is checked for a reaction. A raised, red bump at the injection site is a sign of a positive reaction, which indicates exposure to tuberculosis bacteria.

In some cases, a bruise may form at the injection site, especially if the needle hits a small blood vessel. This bruise is usually mild and fades away within a few days.

If the bruise is large or painful, or if you notice other symptoms, such as itching, swelling, or warmth, you should contact your healthcare provider. These symptoms could indicate an allergic reaction or infection and may require medical attention.

It is important to note that a bruise does not affect the accuracy of the TB skin test. However, if the injection site is too swollen or inflamed, the result may be invalid, and the test may need to be repeated.