Lab method
PYR test
Red = Group A strep and Enterococcus
pie-are / P-Y-R
High-yield clue
A red PYR result identifies Group A strep (S. pyogenes) and enterococci, the two classic PYR-positive Gram-positive cocci.
Overview
A rapid biochemical concept detecting pyrrolidonyl arylamidase (PYRase); hydrolysis releases a compound that turns cherry-red with the added reagent.
Classification
- Enzyme-detection concept
- Rapid identification test
- Cinnamaldehyde color readout
Lab & identification clues
- Cherry-red = PYR positive
- Positive: S. pyogenes and Enterococcus
- Group B strep is PYR negative
- Complements bacitracin for Group A
Associations
- Group A strep confirmation vocabulary
- Enterococcus identification study clue
- Gram-positive cocci differentiation
Commonly confused with
- Bacitracin test
- Hippurate hydrolysis test
Your notes
Original concept summary for coursework. Sources checked: OpenStax Microbiology 2e and NCBI Bookshelf Medical Microbiology; reviewed 2026-06. Describes vocabulary and interpretation concepts only; not a lab protocol and not for handling specimens or identifying patient isolates.