Skin tests (PPD test) and blood tests are good for 1 year while a chest x-ray is good for 5 years.
There are 3 main ways for a person to be tested for TB for employment: skin tests, blood tests and chest x-rays.
TB skin test (PPD test) is a 2-step process typically performed on a person's forearm that requires you to return for the test to be read within 48 hours. Switch requires a TB skin test (PPD) to have a visible read date, negative result and signature of who performed the test. TB skin tests are good for 1 year of the read date.
TB blood test is a single process test done by drawing blood and testing for TB. Switch requires a TB blood test to have a visible result or collected date with a negative result and signature of who performed the test. TB blood tests are good for 1 year of the result or collected date.
Chest x-rays are a single procedure which looks for signs of TB in the lungs. Switch requires a chest x-ray to have a visible statement of "no signs of TB" or something similar and the name of the physician who read the scan. Chest x-rays are good for 5 years of the procedure date.