Video: TB Skin Test – Mantoux Method
This 6-minute instructional video outlines the steps involved in administering and reading the Mantoux skin test, based on Canadian standards.
How Often Is a TB Test Needed?
TB is standing for Tuberculosis, so if you are in contact with those people who are infected by tuberculosis bacterias, the physician will tell you the frequency of which you should be tested. In general, individual can be retested annually since it will expire after 1 year. There isn’t any suggestion on how often to get retested. However, here are some cases you should have a test for TB as following:
Firstly, as we mentioned, you have stayed with somebody recognized or diagnosed to have active TB. Secondly, you’ve got some health condition which can deteriorate the immune system just like HIV, since these conditions can increase your risk extremely for active TB. Thirdly, you are an immigrant from some certain country where TB disease is extremely widespread, or someplace including a shelter, prison and even a few nursing facilities. Lastly, you are injecting some illegal medications.
Video: Skin prick test – Reading the results
What does a positive TB test look like?
The TB skin test is that a medical practioner injects a tiny bit of fluids referred to as PPD which is stand for purified protein derivative underneath the skin on your lower arm. In general, you need to wait around 2-3 days for having the physician checked out if there is a response to the TB bacterium. Then, your physician will determine if you have got a positive reaction or a negative reaction.
First there will be a raised round spot having a red color in the place that you’ve got the skin test. If you are infected by this TB bacterium, you will suffer from a small bump and also the spot which you are injected will go above the normal skin level. The TB skin test which being determined if being positive or negative is dependent upon the volume of the lump surrounding the injection place. Based on CDC, it can be considered as a positive reaction for anybody if the lump is over 15mm, in this case, blisters are usually thought to be a sign of a positive test. For those which are lower than 15mm, there can be several things which also associated with the category you are in.
Commonly we think it is negative when the lump is showing under 15mm. However, there are also a few exceptions. The indication of the lump with a range from 5mm to 10mm can also be regarded as a positive reaction if you are in the risk groups such as drug users, kids and a few immigrants. Furthermore, the indication of the lump over 5mm can as well be deemed positive if you are in extremely high risk group.