Tuberculosis testing is an important part of pre-employment and annual health exams, especially for those clients that work in the healthcare field.
TB is the acronym for tuberculosis. It is a lung disease caused by a small germ called tubercle bacillus. This germ is so small, it can only be seen by using a microscope.
TB is spread through the air from one person to another. The TB bacteria are put into the air when a person with TB disease of the lungs or throat coughs, sneezes, speaks, or sings. People nearby may breathe in these bacteria and become infected.
There are two types of TB infections: Latent TB infection and TB disease. About 10% of the people that are infected with the TB bacteria will develop TB disease. In people with latent TB infection, the bacteria is in their system, but the body’s immune system keeps the bacteria in check, and the person cannot transmit the TB bacteria to others. People with latent TB infection do not feel sick and cannot pass the TB bacteria to others, but are at risk to develop TB disease.
In those with latent TB disease, if the immune system cannot control the infection, then the person develops TB disease. Once they have TB disease they can transmit the bacteria to other people. A person with pulmonary TB disease (in the lungs) may have symptoms such as fever, cough, night sweats, fatigue, and weight loss. You can also develop TB in other parts of the body – the spine, kidneys or brain. This is called extra pulmonary TB. People with extra pulmonary TB may describe pain, weakness or fatigue.
How common is TB? In the United States about 10 million people have active TB disease. But with proper treatment and care the person can be cured of TB disease.
It is important to identify people with latent TB infection to prevent the development of TB disease. The following groups of people are at risk to develop TB Infection:
- Contacts of persons known or suspected to have infectious TB disease
- People who have come to the United States within the last 5 years from areas of the world where TB is common (for example, Asia, Africa, Eastern Europe, Latin America, and Russia)
- Persons who visit areas of the world where TB is common, especially if visits are frequent or prolonged
- People who live or work in congregate settings whose clients are at increased risk for TB disease
- Health care workers who serve clients who are at increased risk for TB disease
- Populations defined locally as high risk for latent TB infection or TB disease, such as medically underserved, low-income persons, or persons who abuse drugs or alcohol
TB testing is done to identify people that have TB infection. The screening tests are: a Mantoux Tuberculin Skin Test – PPD, or a blood test called Interferon-gamma release assays (IGRA) or QFT.
At Mobile Health we offer both types of testing to the clients that come to us for per-employment or annual testing. The PPD test, a small amount of Purified Protein Derivative (PPD) is injected into the layers of the skin on the forearm. The patient then will return within 48 – 72 hours for a reading of the PPD. If the client does not return with the 72 hours for a PPD Reading, they must repeat the PPD implant.
This repeat PPD may be done right away, there is no need to wait. When reading a PPD implant, the trained health care clinician will assess the area where the PPD was implanted. If there is induration, (a palpable, raised hardened area or swelling) it is measured in millimeters (mm), across the forearm – perpendicular to the long axis. Only the hard raised area is measured, redness is not measured.
The determination of a positive PPD depends on both the size of the induration and the person’s medical and epidemiologic risk factors for TB. Clients with a positive result should then have a clinical evaluation, including a chest x-ray.
QuantiFERON®-TB Gold is an alternative screening test for TB. This is an FDA approved blood test. At Mobile Health we offer the Quantiferon-TB (QFT) blood test. The advantage of the blood test is that there is only one visit required for the screening and less likelihood of a false positive test for those who are BCG recipients. Blood is collected in special tubes and analyzed in the lab for the presence of specific proteins. A positive result suggests that infection is likely, and further testing and medical evaluation is required.
TBS is a screening questionnaire at Mobile Health that is used when a client has previously tested positive for a PPD Implant, has had a chest x-ray and a medical provider evaluation that they are free of TB disease. For the clinicians to be able to utilize this screening, the documentation in the record must show documentation of the previous positive PPD – date, size, clinician documenting the positive PPD. There must also be a chest x-ray documented after the positive PPD. This x-ray must state it was an x-ray taken after the PPD and that the x-ray is negative for TB disease. The TBS screening allows for review of the clients’ current symptoms, if any, for TB. If negative, the screening is considered negative for current TB disease. If the client describes current TB symptoms, they should be sent for a clinical evaluation for tuberculosis. What happens if the client cannot show the documentation for a TBS? The client must go back to the agency to discuss the next step. The options are:
- Locate and submit the documentation from the positive PPD and X-ray
- Repeat a PPD implant, with chest x-ray if necessary
- QFT Blood test
Once the agency and client have determined the next step, the patient may return for testing or evaluation, depending on the decision that was made.
Tuberculosis screening is an important service provided by Mobile Health for our clients.
