A Tuberculosis test is common with many pre-employment physicals and is recommended for anyone with a high risk factor. But a lot of technical medical terms are involved in assessing which test to take, the benefits are being tested and what increases the risk of TB exposure and TB symptoms that require urgent medical attention.
Let’s first starts with understanding the TB as a disease and the tests associated for determining TB:
- Tuberculosis: a possibly deadly disease caused by the bacteria Mycobacterium tuberculosis. The disease typically affects the lungs, but affect other parts of the body as well. There are two types of TB:
- Tuberculosis disease( Active tuberculosis) – people with TB disease are sick from TB bacteria that are active, meaning that they are multiplying and destroying tissue in their body. They usually have symptoms of the disease. People with TB disease of the lungs and throat are capable of spreading the germs to others.
- Latent TB infection – people with latent TB have TB germs in their bodies, but they are not sick because the germs are not active. These people do not have symptoms of TB disease, and they cannot spread the germs to others. However, they may develop TB disease in the future.
- Tuberculin: a sterile protein extract of Mycobacterium tuberculosis.
- Purified Protein Derivative (PPD): a solution of tuberculin used to test for tuberculosis.
- Mantoux: the diagnostic test where the PPD solution is injected into the upper layer of the skin to test for tuberculosis.
- Tuberculosis Skin Test (TST): a common term for the process of testing for tuberculosis using the Mantoux method with a PPD injection.
- 2 Step TB Test: A TST where the testing procedure involves 2 separate visits to a medical professional .
- QuantiFERON (QFT): a trademarked blood test used to test for tuberculosis. This test measures how the patient’s immune system reacts to the germs that cause Tuberculosis.
- Tuberculosis Screening Questionnaire (TBS): An assessment done to investigate the possible development of Tuberculosis symptoms in individuals with history of positive tuberculosis test.
For more information on deciding which exam is best for you read this article that discusses the pros and cons of PPD Tests and QuantiFERON tests.
Furthermore, while researching tuberculosis testing it’s important to know that often false positives can incur when using a PPD test to identify the presence of the tuberculin bacteria. These false positives can occur for multiple reasons and the patient will generally be asked to come back for a chest X-ray for further investigation. Below is a list of risk factors that could incur a large induration and a false positive result. Induration refers to the injection that is read done 24-72 hours after the PPD procedure.
5mm induration
- An HIV-positive person
- Persons with recent contacts with a TB patient
- Persons with nodular or fibrotic changes on chest X-ray consistent with old healed TB
- Patients with organ transplants, and other immunosuppressed patients.
10 mm induration
- Recent arrivals (less than five years) from high prevalence countries
- Injection drug users
- Residents and employees of high-risk congregate settings (e.g., prisons, nursing homes, hospitals, homeless shelters, etc.)
- Microbacteriology lab personnel
- Persons with clinical conditions that place them at high risk (e.g., diabetes, prolonged corticosteroid therapy, leukemia, end-stage rental disease etc.)
- Children less than four years of age, or children and adolescents exposed to adults in high-risk categories
15 mm induration
- Persons with no known risk factors for TB
Lastly, it’s always important to be aware of risk factors that could expose you to tuberculosis. Nearly 66% of people worldwide carry the bacteria causing TB. However, this does not meant that they have an active infection and could simply be carrying the bacteria in their body.
Although the TB bacteria is widespread around the world the progression to TB disease is less common.
Circumstances that can lead to a positive TB test result generally include:
- Individuals infected with HIV
- Individuals with history of prior, untreated TB
- Those who are underweight or malnourished
- Injection drug users
- Traveling to Tuberculosis endemic areas
- Common symptoms for a full-blown TB disease infection include:
Tuberculosis symptoms include:
- Prolonged coughing
- Chest pains
- Hemoptysis ( coughing up blood)
- Fever & chills
- Night sweats
- Fatigue
- Loss of appetite
- Unexplained weight loss
Anyone with these symptoms should see a doctor and get a TB screening to check for active TB. Due to the health sensitivity of patients, most healthcare workers in New York State are required to be screened for TB regularly to catch it before it worsens.
If you are interested to schedule a tuberculosis test Mobile Health has 6 locations across New York City and Long Island staffed with medical professionals trained in TB testing. We offer both PPD and QFT options, in addition to the TBS and x-ray options if needed. Clients who use our client portal have the ability to enter their applicant’s PPD results online removing the need for the second visit to Mobile Health.
