If you've been told you need a PPD test for work, school, or immigration purposes, you might be wondering what exactly this test involves and why it's necessary. At EZMED Urgent Care, we provide quick, accurate PPD testing with minimal wait times—because your health and schedule matter.
What Is a PPD Test?
PPD stands for Purified Protein Derivative, a substance derived from the bacteria that causes tuberculosis (
Mycobacterium tuberculosis). The PPD test—also known as the
Mantoux tuberculin skin test—is a simple screening tool used to determine if someone has been infected with TB bacteria
.
It's important to understand:
a PPD test does not diagnose active TB disease. Instead, it identifies
latent TB infection (LTBI)—meaning TB bacteria are present in your body but inactive. Detecting latent TB is crucial because it allows for preventive treatment before the infection becomes active and contagious
.
Who Needs a PPD Test?
You may need TB screening if you:
-
Work in healthcare (hospitals, nursing homes, dental offices)
-
Are starting a new job requiring TB clearance
-
Attend school (especially nursing or medical programs)
-
Have been in close contact with someone diagnosed with active TB
-
Have a weakened immune system (HIV, organ transplant, chemotherapy)
-
Are immigrating to the U.S. or traveling from high-risk countries
-
Live or work in congregate settings (prisons, homeless shelters, residential facilities)
How Does the PPD Test Work?
The PPD test works by measuring your immune system's response to TB proteins. Here's what happens during your visit to EZMED Urgent Care:
Step 1: The Injection (Visit 1)
A trained healthcare provider will:
The procedure takes less than 5 minutes and causes only brief, mild discomfort—similar to a mosquito bite.
Step 2: The Reading (Visit 2)
You must return to EZMED Urgent Care within 48-72 hours (2-3 days) to have your test read. During this visit, we measure any firm swelling (induration) at the injection site—not just redness
.
Important: If you don't return within 72 hours, the test becomes invalid and you'll need to repeat the entire process
.
Understanding Your PPD Test Results
Results are interpreted based on the diameter of induration (firm swelling), not redness:
| Result |
Induration Size |
What It Means |
| Negative |
Less than specified cutoff |
No TB infection detected |
| Positive |
5mm+ (high-risk groups)* |
Possible TB infection |
| Positive |
10mm+ (moderate-risk groups)** |
Possible TB infection |
| Positive |
15mm+ (low-risk individuals) |
Possible TB infection |
*High-risk: HIV-positive, recent TB contacts, organ transplant recipients, immunosuppressed patients
**Moderate-risk: Healthcare workers, recent immigrants from high-prevalence countries, injection drug users, residents of high-risk facilities, children under 4
What Happens If Your Test Is Positive?
A positive result doesn't mean you have active TB or that you're contagious. It simply means you've been exposed to TB bacteria. At EZMED Urgent Care, we'll guide you through the next steps:
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Chest X-ray to check for active lung disease
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Symptom assessment (persistent cough, fever, night sweats, weight loss)
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Possible sputum testing if active disease is suspected
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Referral for treatment of latent TB infection, if appropriate
PPD Test vs. TB Blood Test (IGRA)
While the PPD skin test remains the standard for TB screening, Interferon-Gamma Release Assays (IGRAs)—such as QuantiFERON-TB Gold—are blood tests that offer an alternative. IGRAs are particularly useful if:
Ask your EZMED provider which test is right for your situation.
Preparing for Your PPD Test: What to Know
Before your test:
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No fasting or special preparation required
-
Inform us if you've had a positive PPD test before (we may recommend a chest X-ray instead)
-
Tell us about any immune system conditions or medications (steroids, chemotherapy)
-
Mention if you've received the BCG vaccine
After your test:
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Don't scratch, rub, or cover the injection site with bandages or creams
-
You may shower normally—just avoid scrubbing the area
-
A cold compress can help with itching
-
Return within 48-72 hours for reading
Why Choose EZMED Urgent Care for PPD Testing?
At EZMED Urgent Care in Silver Spring, we make TB screening convenient and stress-free:
✅ Same-day appointments—walk-ins welcome
✅ Fast, accurate placement by experienced providers
✅ Flexible hours for your 48-72 hour return visit
✅ Telemedicine options for follow-up consultations
✅ Competitive pricing—no surprise bills
✅ Quick turnaround for employment and school clearance
