August 19, 2024
Onboarding a new employee? Starting a new job? In addition to all the new hire paperwork, you may also be required to conduct or undergo screenings for diseases, such as tuberculosis (TB). TB tests are widely recommended and often required for employment across many industries, including, but not limited to, health care, education, and social services. Before we dive into the testing itself, let's take a step back and start with the basics.
What is Tuberculosis (TB)?
Tuberculosis is caused by a bacterium called Mycobacterium tuberculosis, which is spread from person-to-person through the air.1 Droplet nuclei containing Mycobacterium tuberculosis are sent into the air when a person with infectious TB coughs or sneezes. TB, which is considered a contagious disease, typically affects the lungs, but it can spread to any part of the body, including the kidneys, spine, and brain.2 While TB is preventable and curable, many people in the United States – and around the world – still suffer from this disease. In fact, one fourth of the world's population is infected with TB.2
Two TB-related conditions exist: latent TB infection (LTBI) and TB disease. The main difference is that LTBI doesn't make you sick. In other words, the TB bacteria remain inactive.3
People with LTBI do not have symptoms and cannot spread TB bacteria to others. However, if left untreated, a person with LTBI may develop TB disease if the TB bacteria become active and cause symptoms, such as a prolonged cough, pain in the chest, and/or coughing up blood or sputum, which is phlegm from deep inside the lungs.4 People with weak immune systems, especially those with HIV infection, have a much higher risk of developing TB disease than people with normal immune systems.3
What TB Testing Options are Available?
TB testing has traditionally relied on a skin test that was developed over 100 years ago.5 However, a simple blood test can now get the job done as well.
TB Skin Test
A TB skin test, also called the Mantoux tuberculin skin test (TST), can be completed at various healthcare facilities, including your local neighborhood MedExpress center. During the test, a small amount of fluid called tuberculin is injected into the skin on the lower part of the arm.6 The person must then return within 48 to 72 hours to have a healthcare provider look for a reaction on the arm. Depending on the size of the raised, hard area, swelling, and risk factors, the healthcare provider will determine if the test was positive or negative.6 A positive result may mean the person is infected with TB bacteria. However, there are factors that can cause false positives, such as prior BCG vaccination, a TB vaccine that many people born outside the U.S. receive. In the case of a positive result, more testing, such as a chest X-ray, sputum culture, or both, may be performed to determine the presence of active TB disease.13
TB Blood Test
TB blood tests are also called interferon-gamma release assays, or IGRAs. IGRAs are whole-blood tests that can aid in diagnosing TB infection.3 Unlike the TB skin test, TB blood tests are completed in a single visit to a healthcare professional, such as MedExpress, making them easier and more convenient for employers and employees. TB blood tests can also be a more accurate form of TB testing.
During a TB blood test, a healthcare provider draws a patient's blood and sends it to a laboratory for analysis and results. A positive result means the person is infected with TB bacteria, but additional tests are needed to determine if the person has LTBI or TB disease.
Are You An Employer? We'll Bring TB Testing Directly to You
Through MedExpress' episodic on-site services, which we can bring right to your workplace, we offer TB skin tests and blood tests.
Most employers prefer to utilize the TB blood test, such as QuantiFERON-TB Gold Plus (QFT-Plus), for the simple fact that it only requires one visit rather than two. However, a positive result still requires additional tests to determine if the person has LTBI or TB disease. The blood test is also more convenient and relies on objective lab-based testing.
QFT-Plus has been used to screen patients for TB infection more than 100 million times since its launch.7 With a 94 percent sensitivity, QFT-Plus offers fewer false positive results than a traditional TB skin test.8 QFT-Plus is endorsed by the WHO, embraced by the UN and IPPA and among the WHO's 120 essential diagnostic tests.9
Interested in learning more about bringing TB testing directly to your employees?
Who's at Risk in the Workplace?
In the workplace, employees in health care and other settings where many people share a space for extended periods of time are at risk of contracting TB.10 The spread of TB occurs through the air when someone with TB disease of the lungs or throat coughs, speaks, or sings.11 According to the CDC, TB cannot be spread by certain physical interactions, such as shaking someone's hand or kissing, sharing food, drink, or toothbrushes, or touching bed linens or toilet seats.11
Some examples of places where the spread of TB often occurs are healthcare facilities, correctional institutions, long-term care facilities for the elderly, schools, daycares, homeless and social assistance shelters, and emergency shelters. According to the National Institute for Occupational Safety and Health (NIOSH), "transmission of disease in these spaces is most likely to occur when patients, prisoners, or shelter clients have unrecognized TB or have received ineffective or incomplete treatment for known disease."10
Preventing TB
TB is preventable and, in most cases, treatable. People diagnosed with LTBI who receive treatment can prevent the subsequent development of active TB disease. Available anti-TB drugs can usually cure someone diagnosed with TB disease. Alternative regimens of medications can often even cure people with drug-resistant strains of the disease.10
But how can transmission of TB be prevented in the first place – especially in the workplace? According to the NIOSH, a TB infection control program should be based on the following three levels of a hierarchy of controls10:
- Administrative controls, such as written safety policies or training, which reduce risk of exposure
- Environmental controls, which prevent spread and reduce concentration of infectious TB droplet nuclei
- Respiratory-protection, which further reduce risk of exposure in special areas and circumstances
World Tuberculosis Day
Looking for a way to educate yourself and/or your team about TB? Each year World Tuberculosis Day is observed on March 24. On this date in 1882, Dr. Robert Koch announced his discovery of the rod-shaped bacterium that causes TB: Mycobacterium tuberculosis.12 The CDC recognizes this day annually with a theme, as well as activities and resources to bring awareness to TB.
Testing for TB is especially important in work environments where transmission of the disease is a risk – most notably in healthcare facilities. If you're not sure where to begin, MedExpress is here to help. We have the ability to bring TB testing directly to your worksite and knowledgeable healthcare professionals who can offer treatment to anyone with a positive TB result.
Originally published February 2019. Updated August 2024.
References:
1 CDC. Tuberculosis (TB): Basic TB Facts. Last updated March 20, 2016. Accessed December 19, 2018.
2 CDC. About Tuberculosis. Last updated December 19, 2023. Accessed August 19, 2024.
3 CDC. About Inactive Tuberculosis. Last updated December 20, 2023. Accessed August 19, 2024.
4 CDC. Signs and Symptoms of Tuberculosis. Last updated March 6, 2024. Accessed August 19, 2024.
5 QIAGEN. What is QuantiFERON-TB Gold Plus? Accessed December 20, 2018.
6 CDC. Testing for Tuberculosis: Skin Test. Last updated April 22, 2024. Accessed August 19, 2024.
7 QIAGEN. QIAGEN Reaches Milestone With 100 Million QuantiFERON tests used to detect TB. Accessed May 31, 2022.
8 QIAGEN. Why Should Providers Choose QFT-Plus. Last updated June 2017. Accessed December 19, 2018.
9 QIAGEN. TB testing with QFT-Plus. Accessed May 31, 2022.
10 CDC/NIOSH. About Work-related Tuberculosis. Last updated April 2, 2024. Accessed August 19, 2024.
11 CDC. Tuberculosis: Causes and How It Spreads. Last updated March 6, 2024. Accessed August 19, 2024.
12 CDC. Tuberculosis (TB): World TB Day. Last updated March 24, 2017. Accessed December 20, 2018.
13 CDC. Tuberculosis Vaccine. Last updated June 14, 2024. Accessed August 19, 2024.