A tine test is a medical test employed to find out whether a person may have been exposed to bacteria responsible for causing tuberculosis. In the past, this test was regularly used to look for the presence of bacteria, but not as the final test to diagnose a current case of tuberculosis. This is due to the fact that a person may test positive without having tuberculosis. Today, the tine test isn’t used very often, as more accurate tests have been developed.
To perform a tine test, a medical professional uses a small instrument with four to six short needles protruding from it to prick the skin. These needles are coated with tuberculosis antigen. An antigen is a substance that causes the body to produce antibodies by provoking the immune system into a response. The needles inject the antigen just beneath the skin of the patient’s forearm. In most cases, the medical professional marks the area to which the test was applied in order to make reading the test results easier.
After receiving the tine test, the patient must wait about two to three days to have the results read. He will then return to the medical facility and allow medical personnel to look at the same area of skin to which the needles were applied. If there is redness and swelling present, this indicates the presence of the bacteria and the needed for further diagnostic testing. The reaction caused by a positive test can be likened to the swelling and firmness of a mosquito bite; negative tests may be a bit red, but the papules are not present.
Abnormal, or positive, tine test results indicate tuberculosis infection. This means the patient has been infected with the bacteria that cause tuberculosis. However, this result does not indicate that the patient has an active infection. Instead it means that he has been exposed and infected at some point, so his body responded to the antigen under his skin. A chest x-ray is necessary to determine whether or not the infection is active.
There’s nothing special a person needs to do before a tine test. However, those with rashes or other forearm skin irritation may opt to have the test performed on other parts of the body. Typically, the test isn’t very painful. Many people note only a minor stinging sensation from the tiny needles. Others may notice minor itching or burning after the test.