Tuberculosis testing might not be the first thing that comes to mind when we talk about pre-employment screening, but it continues to be an important part of occupational health, especially in healthcare and other environments where employees may have a greater risk of exposure.
TB screening requirements can show up in hospitals, long-term care facilities, home healthcare, laboratories, correctional healthcare settings, emergency medical services, and positions involving close contact with vulnerable populations. The CDC currently recommends baseline TB screening for all U.S. healthcare personnel upon hire, although specific requirements can vary by state, facility, and position.
With employers hiring across larger geographic areas and healthcare organizations managing increasingly mobile workforces, we are seeing TB testing come up more frequently in occupational health conversations. The good news is that employers have several testing options.
PPD or TST: The Traditional Skin Test
The PPD, also called a Tuberculin Skin Test or TST, is probably the most familiar TB test.
A small amount of tuberculin is placed under the skin of the forearm. The candidate then has to return to the provider 48 to 72 hours later so a trained professional can read the reaction.
The biggest advantage of PPD testing is cost. It is generally a simple and economical option.
The downside? It requires another visit. If the candidate does not return during the required reading window, the test may need to be repeated.
What About a 2-Step PPD?
This is where TB orders can get a little confusing.
A 2-Step PPD is not simply reading the same test twice. The first skin test is placed and read. If it is negative, a second skin test is performed 1 to 3 weeks after the first test is read.
2-step testing can be used to establish an accurate baseline for people who may undergo periodic TB testing, including certain healthcare personnel.
That means considerably more coordination than a blood test, with multiple visits required to complete the process.
QuantiFERON-TB Gold Plus: One Visit, No Skin Reading
QuantiFERON-TB Gold Plus, often shortened to QuantiFERON, QFT, or TB Gold, is an IGRA blood test.
Instead of placing something under the skin, blood is drawn and sent for laboratory testing. One of the biggest advantages for employment screening is convenience. There is no requirement for the candidate to return 48 to 72 hours later just to have the test read.
Another major advantage is that TB blood tests are preferred for people who have received the BCG vaccine, because BCG vaccination can cause a false-positive skin test reaction but does not affect TB blood test results.
The tradeoff is typically higher cost compared with a PPD and the need for a collection location capable of properly drawing and processing the specimen.
T-SPOT.TB: Another Blood Testing Option
T-SPOT.TB is another FDA-approved IGRA blood test. Like QuantiFERON, it requires a blood draw rather than a skin test and does not require the candidate to return for a skin reading.
For employment programs, QuantiFERON and T-SPOT can both offer an easier candidate experience compared with PPD testing, particularly when coordinating screenings across multiple locations.
And Where Does the Chest X-Ray Fit In?
A chest X-ray is not interchangeable with a PPD, QuantiFERON, or T-SPOT screening test.
Instead, chest X-rays are generally part of the additional medical evaluation when someone has a positive TB test, symptoms concerning for TB disease, or a documented history of a previous positive test. A positive skin or blood test indicates TB infection, but additional evaluation is needed to determine whether someone has inactive TB or active TB disease.
So, Which TB Test Should You Order?
There isn’t one answer for every employer.
PPD testing can provide a lower-cost solution, but it requires return visits. 2-step PPD testing adds even more coordination when a baseline is required. QuantiFERON and T-SPOT cost more but can simplify the candidate experience by eliminating the return visit for a skin reading.
The key is understanding what the employer, position, facility, and applicable regulations actually require before placing the order. CDC guidance also notes that state and local requirements may differ.
When it comes to occupational health, getting those details right upfront can mean fewer missed appointments, fewer repeat tests, and a much smoother onboarding experience for everyone.
