Is the skin test as accurate as a chest x-ray for tb?

No: The skin test is a screening test to see if you might have been exposed to or contracted tb. If the skin test is positive, a chest x-ray is done to see if you have active tb.

TB test: The skin test (tuberculin, ppd) is very accurate in detecting the presence of tuberculosis. A chest x-ray will show positive findings of tuberculosis only if there is active disease. A negative chest x-ray does not rule out tuberculosis but a positive tuberculin will, despite absence of symptoms.

Yes and no: The skin test almost always shows if you have been exposed to TB but does not mean you have active disease. The chest x-ray indicates if you have significant lung infection, but does not show early or very mild infections.

Common mistake BCG: Some people get bacille calmette guerin (bcg), which is a TB vaccine used worldwide (except U.S.) and can cause life-long false positive skin test. Ignorant public health agencies have been known to force TB treatment in such cases. For people who received bcg, TB blood testing is much more specific. You can read about this at the cdc website: http://www.Cdc.Gov/tb/topic/testing/default.Htm.