Microbiology All the following are true about IGRA (Interferon gamma release assays) except. A Differentiates active and latent TB B Also called quantiferon TB gold assay C Alternative to tuberculin skin test D Urine is used as sample 💡 Explanation All the following are true about IGRA (Interferon gamma release assays) except. ✓ Correct Answer: D. Urine is used as sample