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Medical Devices

IDI-Strep B Assay - K022504

This is a brief overview of information related to FDA's declared substantially equivalent to a legally marked device for this product. See the links below to the manufacturer's submitted 510(k) Summary that provides an understanding of the basis for a determination of substantial equivalence.

Product Name: IDI-Strep B Assay
 Infectio Diagnostic (I.D.I.) Inc.
2050, boul, Rene-Levesque O, 4e etage, Sainte-Foy, Quebec, Canada
Clearance Date: 
November 18, 2002
Clearance Letter:

What is it? The IDI-Strep B assay is a new laboratory test to detect Group B Streptococcus (Group B Strep) in pregnant women. The new test uses a Cepheid Smart Cycler® instrument to analyze swab samples taken from the vagina and rectum.

How does it work? This test does not use a standard culture method to grow the Group B Strep bacteria. Rather, the Cepheid Smart Cycler® instrument detects the DNA of Group B Strep. It can provide results in 1 hour, if facilities can provide round-the-clock testing. In contrast, the standard method of culture testing takes 18 to 48 hours for results. The IDI-Strep B test is the first non-culture test that meets the performance criteria recommended by the Centers for Disease Control and Prevention (CDC) guidelines – at least 85% sensitive compared to culture methods. Because of this, it can be used instead of standard culture methods.

When is it used? The test is used on a specimen from a woman who is 35-37 weeks pregnant, or when labor begins (if earlier testing was not done), and the results are available in sufficient time to allow four hours of antibiotic treatment before delivery. This antibiotic treatment of the mother during labor can prevent transmission of Group B Strep to her newborn.

What will it accomplish? A positive result with the assay shows that a woman is colonized with Group B Strep. A woman with Group B Strep is offered antibiotic treatment during labor (but before delivery) to prevent Group B Streptococcal disease in her baby. Although the IDI-Strep B? assay can be used without culturing, culturing is still needed to determine an effective antibiotic treatment for women who are allergic to penicillin.

When women begin labor before routine testing has been done, or if they have had no prenatal care, the IDI-Strep B? assay could be done within 1 hour, in time to give antibiotic treatment to women whose time to delivery is longer than 5-6 hours. Unnecessary antibiotic use for those women with no evidence of Group B Step would also be avoided.

When should it not be used? The IDI-Strep B? is only useful if results can be available at least 4 hours before a woman delivers her baby. Thus, the assay should not be used for women in labor unless a facility can do the test round-the-clock. The test should also not be used in laboratories without molecular diagnostic testing experience because reliable results depend on training and experience.

Additional information: Substantial Equivalence letter will be available at:

Page Last Updated: 09/05/2013
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