Both the PPD (Mantoux) skin test and the QuantiFERON-TB Gold blood test screen for tuberculosis exposure. Both are accepted by schools, nursing programs, healthcare employers, and most immigration applications. The choice between them comes down to three factors: number of visits, BCG vaccination history, and what your specific program asks for.
The PPD skin test is a two-visit test. We inject a small amount of TB protein in your forearm at the first visit, and you return 48 to 72 hours later for a trained reader to measure the response. If you miss the reading window, the test must be repeated. The advantage: it is the long-standing standard, accepted everywhere.
The QuantiFERON-TB Gold blood test is a single-visit test. We draw a single small tube of blood; the lab measures your immune response to TB-specific proteins. Results post to your secure online portal in 24 to 72 hours. The advantage: one visit, no return reading appointment, and the test is not affected by BCG vaccination.
BCG vaccination is the main reason to choose QuantiFERON over PPD. BCG (Bacillus Calmette-Guérin) is a TB vaccine used in many countries outside the United States. People who received BCG can produce false-positive PPD skin reactions, which can lead to unnecessary follow-up testing. QuantiFERON is not affected by BCG and is generally recommended for BCG-vaccinated individuals.
For nursing programs and healthcare employers, both tests are accepted in most cases — but a growing number of nursing programs specifically request QuantiFERON because of the single-visit convenience and the BCG-sensitivity issue. Check your program’s paperwork; if it does not specify, either test is fine. Our Ashburn lab charges $89 either way.
Key takeaways
- PPD: two visits, 48 to 72 hour reading window required
- QuantiFERON: one visit, no return appointment
- BCG-vaccinated → choose QuantiFERON
- Both $89 at our Ashburn lab