Clinical Microbiology


CHROMagar™ StrepA

Click on the picture for
Packaging / Colonies appearance

For screening of Group A Streptococci in throat samples 

Typical Appearance of microorganisms

Group A Streptococcus → Orange to red
Other oral Streptococci → colorless or blue

Order References 

Please use these references when
contacting your local distributor:
5000 mL........... SP372
25 L................. SP373-25
Bulk on request
To download the certificate of analysis, please indicate your lot number below :


Medium Performance

CHROMagarTM StrepA is a new chromogenic formulation allowing for an easy to read and straight forward color differentiation of GAS colonies (in orange to red) among the other bacteria in the complex throat flora (colorless or blue colonies).

Medium Description

Gain flexibility using powder rather than ready to use plates: Use the entire pack, or just a portion if there is a need for a smaller number of plates. If kept under appropriate storage temperature, CHROMagarTM StrepA has a more than 18 months shelf life. This flexibility is essential to avoid the waste resulting from expired-unused plates. 

Please refer to our notice and Material Safety data sheet for complete information about the medium. 
CHROMagar™, Rambach™, AquaCHROM™ are trademarks created by Dr. A. Rambach.

Last Update: 19-Jun-2019

Focus on Streptococcus pyogenes

Streptococcus pyogenes infection is responsible for nearly all Streptococci caused bacterial pharyngitis, therefore the specific target of current strep throat screening methods. 

Rapid and accurate detection of this microorganism in throat specimens, particularly in children and elderly patient, is essential to start antibiotic therapy, to prevent complications and reduce the risk of transmission to other persons.

Patients are commonly tested for the presence of GAS using antigen detection test that provide results in 15-20 minutes, but with a positive predictive value of ~70-90 % and a rate of false negatives ~10-20 %. However, throat culture is used primarily as a confirmatory test with definitive results requiring 24 h.



Validation and implementation of Colorex™ CHROMagar™ Strep A agar on WASP™/WASPLab™ for screening for Streptococcus pyogenes using the ESwab™


Mark Gaskin et Al. ASM 2019

Digital detection and the use of Artificial Intelligence to detect Group A Streptococcus using a chromogenic agar


Cynthia C. Kayak Alverno Laboratories, Hammond, IN ASM San Francisco 2019

Automated Detection of Streptococcus progenies Pharyngitis by use of Colorex Strep A CHROMagar and WASPLab Artificial Intelligence Chromogenic Detection Module Software


Tam T. Van, Kenneth Mata, Jennifer Dien Bard Journal of Clinical Microbiology October 2019
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