FDA recently granted premarket notification (510(k)) clearance to the Simplexa group A strep direct kit by Focus Diagnostics, Cypress, Calif, the clinical laboratory products business of Quest Diagnostics. The agency also categorized the test as moderate complexity under the terms of the Clinical Laboratory Improvement Amendments of 1988 (CLIA). The Simplexa group A strep direct test is a real-time polymerase chain reaction (PCR) assay for the detection of group A Streptococcus bacteria directly from throat swabs.

Group A Streptococcus is a gram-positive bacterium responsible for a wide range of infections, the most prevalent of which are known as strep throat (pharyngitis), and occur when the bacteria colonizes in the throat. Strep throat is most common in children between ages 5 and 15. More than 600 million cases of strep pharyngitis are estimated to occur worldwide each year. Sore throat, a common symptom of strep pharyngitis, is responsible for 7.3 million pediatric outpatient visits annually in the United States.

Because strep pharyngitis shares symptoms in common with the flu and other respiratory conditions, such as painful sore throat and fever, laboratory testing is an important aid in diagnosis. Untreated strep infections can lead to serious conditions, including rheumatic fever and scarlet fever. Strep is typically treated with a course of antibiotics.

Hollis J. Batterman, MD, Focus Diagnostics.

Hollis J. Batterman, MD, Focus Diagnostics.

“Fast, reliable diagnosis of strep can make a world of difference in the effectiveness of treatment for this highly prevalent and painful bacterial infection,” says Hollis J. Batterman, MD, medical director for infectious diseases at Focus Diagnostics. “Our Simplexa direct strep test uses a proprietary technique to provide results in as quickly as an hour, compared to up to two days for culture, and has better specificity than rapid antigen tests, which are prone to false negatives. Faster diagnosis and subsequent treatment can minimize the risks of infection of others, inappropriate use of antibiotics, and progression to more advanced and potentially life-threatening disease.”

“Simplexa direct strep reflects our vision to provide diagnostic insights that help physicians and patients take prompt, well-informed actions to achieve a favorable outcome,” Batterman adds.

Designed for use on the Integrated Cycler by 3M, St. Paul, Minn, Simplexa tests employ real-time PCR technology to detect DNA or RNA in viruses, bacteria, and other analytes. Using a proprietary chemistry technique that eliminates the nucleic acid extraction process typical of molecular diagnostics, Simplexa tests can produce results in as little as 1 hour.

The Simplexa group A strep direct test is intended for the in vitro qualitative detection of group A Streptococcus from throat swabs collected from human patients with signs and symptoms of pharyngitis, such as sore throat. In clinical studies, the test showed strong performance when compared to culture tests, with 97.4% sensitivity and 95.2% specificity.

Molecular tests are typically categorized as high complexity under CLIA, and can therefore be performed only in certain reference and hospital labs meeting high-complexity requirements. FDA’s categorization of the Simplexa direct strep test as moderate complexity will permit some physician offices, community hospitals, health clinics, and integrated delivery networks to perform the test directly.


Michelle Tabb, PhD, Focus Diagnostics.

“With moderate complexity classification and a streamlined workflow, our Simplexa direct strep test could potentially benefit a large number of the many millions of people suspected of strep each year,” says Michelle Tabb, PhD, vice president of research and development at Focus Diagnostics. “That’s a major advantage over other molecular methods of diagnosing group A strep, which may be more labor intensive to perform.”

A Simplexa kit was the first test to receive FDA clearance for aiding in the detection and differentiation of the 2009 H1N1 influenza virus, in May 2010. Additional Simplexa tests aid in the detection and differentiation of Clostridium difficile, and herpes simplex virus 1 and 2, influenza A, influenza B, and respiratory syncytial virus.

The Simplexa direct strep test was CE marked for distribution in the European Union in February 2015. The test kit is now available directly in the United States and internationally through the global distribution network of Focus Diagnostics. For further information, visit Focus Diagnostics.