In medicine and statistics, gold standard test is usually diagnostic test or benchmark that is the best available under reasonable conditions. Other times, gold standard is the most accurate test possible without restrictions. Both meanings are different because for example, in medicine, dealing with conditions that would require an autopsy to have a perfect diagnosis, the gold standard test would be the best one that keeps the patient alive instead of the autopsy.
Youâll use intermediate strength (5 T.U.) PPD in a tuberculin syringe that has a 1/2-inch, 26- or 27-gauge needle. Make sure the bevel edge of the needle is facing up, and insert the needle beneath the skin (Figure 1).ouâll use intermediate strength (5 T.U.) PPD in a tuberculin syringe that has a 1/2-inch, 26- or 27-gauge needle. Make sure the bevel edge of the needle is facing up, and insert the needle beneath the skin (Figure 1).
The TB blood test can be done instead of a TB skin test (Mantoux). You should have a TB blood (or TB skin test) if you: 1  have HIV infection or your immune system is not very strong.  Children less than 5 years old should have the TB skin test instead of the TB blood test. Ask your health care provider. They will draw a small amount of blood and send it to a laboratory. Your health care provider should tell you if your test result is ânegativeâ or âpositiveâ in a few days. A ânegativeâ TB blood test result usually means that you donât have TB germs in your body.