Tuberculosis (TB) is an infectious illness that mainly affects the lungs, and can potentially be fatal if left untreated. Droplets produced from coughs and sneezes carry tuberculosis-causing germs from person to person. If you believe you may have been exposed to someone with TB or have tuberculosis symptoms, you should get a TB skin test immediately.
A tuberculin skin test, also known as a PPD or Mantoux tuberculin test, will help you confirm whether you’ve been exposed to tuberculosis. The test is performed by injecting a small quantity of TB protein (antigens) under the skin’s top layer on the inner side of the patient’s forearm. If you’ve been exposed to TB germs (a bacteria called mycobacterium tuberculosis), your skin will react to the antigens with a solid, red bump within two days.
The antigens used in tuberculin skin tests are pure protein derivatives (PPD). You will get a carefully-calibrated injection of PPD beneath the skin of your forearm. This is a reliable method for detecting tuberculosis. This diagnosis is also supported by symptoms, screenings, or testing (such as a chest x-ray).
Do UrgentMED Urgent Care Clinics Provide TB Tests?
Many people with suspected TB wonder whether they need to go to the hospital for a TB skin test. UrgentMED urgent care clinics offer a range of diagnostic testing, including tuberculosis testing with a TB Skin Test (PPD).
We have state-of-the-art facilities and a certified on-site lab where we test samples and provide accurate results quickly. We have an extensive family of urgent care clinics across Los Angeles, so you can walk into your nearest location for a TB test — and you don’t even need to make an appointment.
Unlike most TB testing experiences, UrgentMED doesn’t require you to visit multiple times! We will notify you of your results as soon as they come back from the lab. UrgentMED also offers QuantiFERON testing to detect TB.
Why You May Need a TB Test
A TB/PPD test detects tuberculosis bacteria in patients, including:
- Those who have been in close contact with a TB-affected person
- Healthcare workers who have likely been exposed to tuberculosis
- People with TB symptoms, including an ongoing cough, unexplained weight loss, and night sweats
- People with abnormalities in their chest x-rays
- Individuals with an impaired immune system (such as patients with HIV) or who recently had an organ transplant
You should should avoid a TB skin test if you have:
- A confirmed tuberculosis infection
- Skin rashes that would make it difficult to read the skin test
- Previously experienced a severe reaction to TB antigens
How to Prepare for a TB Skin Test
Before being tested for TB, tell your healthcare professional if you:
- Have had tuberculosis in the past
- Have symptoms of TB, such as unexplained weight loss, an ongoing cough, or night sweats
- Have previously had a severe reaction to a TB skin test
Risk Factors to Inform Your Treatment Provider
You should also inform your healthcare provider if:
- You have had contact with an individual who has TB
- Your job as a healthcare worker might expose you to patients with TB
- You have traveled to or lived in a country where tuberculosis is common
- You have been administered a TB vaccination. This contains a BCG (bacilli Calmette-Guérin) bacteria akin to bacteria that cause tuberculosis.
- You have been been treated with corticosteroids or other medicines that can harm your immune system
- You are infected with HIV
- You have skin rashes that may make it difficult to read your skin test
Talk to your healthcare provider about any concerns regarding the need for the test, as well as the risks, how the test will be performed, and what the results will mean.
How We Perform TB Skin Tests at UrgentMED
These are the steps we follow at UrgentMED during a PPD test:
- You will sit down and turn up the inner side of your forearm.
- The surface of the skin where the TB test will be performed is cleaned and allowed to dry.
- A small TB antigen shot (purified protein derivative/ PPD) is placed under the skin’s top layer. You may feel a quick sting or pinch from the needle.
- The fluid makes a wheal (little bump) under the skin. The doctor may draw a small circle around the TB test area with a pen.
- That’s it! You will not need to return to the clinic for a follow-up. We will notify you of your results when they come back from the lab.
Are There Any Risks of a TB Skin Test?
There is minimal risk of having a severe reaction to the PPD test, especially if you have had TB. However, an allergic reaction can cause pain and swelling at the site, and a sore may develop.
Some patients wonder whether you can get a TB infection from the PPD skin test. The answer is no, this is not possible because no live TB bacteria are used in the test.
If you are pregnant or breastfeeding, you can rest assured that a PPD test is safe for you as well.
What Happens After the TB Test?
The skin test location may become somewhat red. Do not scratch the area since this might lead to redness and swelling, and may make the test results inaccurate. If the irritation persists, place a cool washcloth over the area and wait for it to dry.
A positive reaction might be slightly painful. Talk to your doctor at UrgentMED if you have:
- A high fever
- Inflammation and swelling in the arm
- Puffy lymph nodes under the arm
TB Test Results
When the test site on the skin only turns red, it is unlikely that you have been infected. Infection with tuberculosis germs can cause a hard, red lump. A result is determined within 2–3 days after the test by measuring the size of the hard bump (not the red region). The physician evaluates the likelihood of a tuberculosis infection by examining the test site.
Sometimes, even a minor bump could indicate an infection in high-risk individuals. Those at minimal risk for contracting tuberculosis must have a more prominent bump to be diagnosed with TB. Your UrgentMED healthcare professional will consider all of these factors when analyzing your test results.
Risk Levels for a TB Infection
- Individuals with HIV
- Those who have had recent close contact with someone who has an active TB infection
- Individuals who have either TB symptoms or a positive chest x-ray
- Those who use corticosteroid-containing medications or biologics (used to treat Crohn’s disease and rheumatoid arthritis) for extended periods
- People who have recently moved from or traveled to a country with a high TB rate
- Intravenous drug users
- Nursing home residents
- Healthcare workers in hospitals, schools, nursing homes, and prisons
- Children (ages 4 to 18) who are exposed to a high-risk adult
- Homeless individuals
- People who are 10% or more below their optimal body weight
- Those with renal failure
- People with diabetes, leukemia or cancer
- Individuals who have had part of their gut surgically removed (gastrectomy)
Those who fall outside of these risk categories are considered low-risk for a TB infection.
Limitations of the TB Skin Test (PPD)
A positive reaction typically stays visible for about a week. However, a positive tuberculin test result does not indicate an active infection. This TB skin test does not distinguish between a live and dormant infection (latent TB). It also cannot differentiate between tuberculosis infection and TB vaccine (BCG vaccination). Further tests, such as a chest x-ray or sputum culture, are typically performed to determine whether you have a current TB infection.
At UrgentMED, we have diagnostic testing facilities and a certified lab on-site. You can trust us to provide the best services under a single roof in a comfortable, hygienic setting. Our team will provide all of the details about the test and how we read the results.
Visit an UrgentMED Clinic for Your TB Test and Other Diagnostic Testing Needs
If you think you might have contracted a TB infection, visit UrgentMED as soon as possible for a TB skin test. Identifying the disease early and receiving timely treatment are critical for the best outcomes. You don’t need to schedule an appointment, as all of our locations are “walk-in” clinics. If you suspect you have TB, visit your nearest UrgentMED center today.
We have a large number of urgent care clinics throughout Southern California. With minimal wait times, experienced healthcare professionals, and highly affordable services, we’re the trusted choice for TB testing. To learn more, contact us online today.