The ACON® Strep A Twist Rapid Test Device is a rapid chromatographic immunoassay for the qualitative detection of Strep A antigen from throat swab specimens to aid in the diagnosis of Group A Streptococcal infection. This test is indicated for professional and point of care use only.

Device Description

The ACON® Strep A Twist Rapid Test Device is a qualitative, lateral flow immunochromatographic assay for the detection of Strep A antigen from a throat swab. The test is a heterogeneous, sandwich immunoassay, based on the principle of antigen-antibody immunochemistry, which uses a mixture of polyclonal antibodies to reliably produce a visually discernible colored line in the test region if Strep A antigen is present at a concentration of roughly 2.5 x 102 organisms per swab or greater.

AI/ML Overview

Here's a breakdown of the acceptance criteria and the study proving the device meets them, based on the provided text:

Acceptance Criteria and Device Performance

Acceptance Criteria (from predicate device comparison)	Reported Device Performance (ACON Strep A Twist Rapid Test Device)
Intended Use: Rapid chromatographic immunoassay for qualitative detection of Strep A antigens from throat swab specimens to aid in diagnosis of Group A Streptococcal infection.	Meets: "a rapid chromatographic immunoassay for the qualitative detection of Strep A antigen from throat swab specimens to aid in the diagnosis of Group A Streptococcal infection."
Indications for Use: Professional & point of care use.	Meets: "professional and point of care use only."
Intended Specimen: Throat Swab	Meets: "from throat swab specimens"
Endpoint: Colored Lines	Meets: Device produces "a visually discernible colored line"
Methodology: Membrane Particle Assay	Meets: "qualitative, lateral flow immunochromatographic assay" (which is a type of membrane particle assay)
Extraction Time: 1 minute	Meets: "1 minute"
Test Time: 5 minutes	Meets: "5 minutes"
Organism detection: Strep A specific	Meets: "Strep A specific" (demonstrated through specificity study)
Sensitivity (compared to culture): Not explicitly stated as a numerical acceptance criterion, but clinical accuracy is evaluated against it.	90% (86-94% 95% CI)
Specificity (compared to culture): Not explicitly stated as a numerical acceptance criterion, but clinical accuracy is evaluated against it.	94% (92-96% 95% CI)
Overall Agreement (compared to culture): Not explicitly stated as a numerical acceptance criterion, but clinical accuracy is evaluated against it.	93% (91-95% 95% CI)
Negative Agreement (compared to predicate): Not explicitly stated as a numerical acceptance criterion, but clinical accuracy is evaluated against it.	100% (99-100% 95% CI)
Positive Agreement (compared to predicate): Not explicitly stated as a numerical acceptance criterion, but clinical accuracy is evaluated against it.	94% (89-97% 95% CI)
Overall Agreement (compared to predicate): Not explicitly stated as a numerical acceptance criterion, but clinical accuracy is evaluated against it.	98% (97-99% 95% CI)
Cross-reactivity: No cross-reactivity with common respiratory pathogens	Meets: "None of the organism demonstrated any cross-reactivity in the test." (20 organisms tested)
Interference: No interference from common oral/throat medications or substances.	Meets: "No interference to an expected negative or positive result was observed" (9 substances tested, plus whole blood and mucin)
Intra and Inter-assay Variability: Expected results >99% of the time.	Meets: "expected results >99% of the time"
Lot-to-Lot Variability: Highly reproducible.	Meets: "highly reproducible"
Minimum detectable level: Roughly 2.5 x 10^2 organisms per swab or greater.	Meets: "roughly 2.5 x 10^2 organisms per swab or greater." (also stated in sensitivity study that 7 strains showed ~10^0 and 2 strains showed ~10^1 organisms per swab, within the general magnitude)

Study Information:

Sample size used for the test set and the data provenance:
- Sample Size: 758 patient specimens.
- Data Provenance: Multi-center clinical evaluation. The country of origin is not explicitly stated, but the sponsor is located in San Diego, California, suggesting a US-based study. It is a retrospective study, as specimens were collected from "patients presenting with signs and symptoms of pharyngitis."
Number of experts used to establish the ground truth for the test set and the qualifications of those experts:
- The ground truth (Strep A confirmed culture technique) is a laboratory method, not established by human experts in the way a radiologist reads images. Therefore, the concept of "number of experts" and "qualifications of experts" does not directly apply to the primary ground truth methodology used for the clinical accuracy study.
Adjudication method for the test set:
- Not specified. The study directly compared the ACON® Strep A Twist Rapid Test Device to a "commercially available Strep A test device" (QuickVue In-Line One-Step Strep A) and to "the customary Strep A confirmed culture technique." There is no mention of an adjudication process between different readers or interpretation of the index device.
If a multi-reader multi-case (MRMC) comparative effectiveness study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance:
- No, an MRMC comparative effectiveness study involving human readers with and without AI assistance was not done. This device is a rapid diagnostic test for direct visualization of colored lines, not an AI-assisted interpretation device. The "multi-center" evaluation refers to where samples were collected, not to multiple human readers interpreting cases.
If a standalone (i.e. algorithm only without human-in-the-loop performance) was done:
- Yes, the performance data presented (Sensitivity, Specificity, Agreement) for the ACON® Strep A Twist Rapid Test Device are standalone performance metrics. While a human reads the colored lines, the device itself generates the result indicating presence or absence of Strep A. There isn't an "algorithm" per se in the way AI would be considered, but rather a biochemical reaction. The "standalone" here refers to the device's inherent ability to detect the antigen, which is then interpreted by a user.
The type of ground truth used:
- Primary Ground Truth: Strep A confirmed culture technique. Culture is widely considered the gold standard for diagnosing Group A Streptococcal infection.
- Secondary Comparison: Another commercially available Strep A test device (Quidel QuickVue In-Line One-Step Strep A) was used for agreement comparison.
The sample size for the training set:
- The provided document does not explicitly mention a separate "training set" for the device's development. This is common for immunochromatographic assays where the device design and antibody selection are based on scientific principles rather than machine learning training data. The "Sensitivity" section mentions evaluating 9 different strains of Strep A to determine minimum detectable levels, which could be considered part of the R&D/optimization phase, but not a formal "training set" in the AI sense.
How the ground truth for the training set was established:
- As no formal training set is identified in the document (in the context of machine learning), the establishment of ground truth for a training set is not applicable. The development of the device's capabilities would have relied on laboratory testing against known concentrations of Strep A antigens and strains.

Summary

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FEB 1 0 2003

Summary of Safety and Effectiveness 7.

510(k) Summary

This summary of 510(k) safety and effectiveness information is being submitted in accordance with the requirements of SMDA 1990 and 21 CFR 807.92.

The Assigned 510(k) number is ________________________________________________________________________________________________________________________________________________ ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

Submitter: ACON Laboratories, Inc. 4108 Sorrento Valley Boulevard San Diego, California 92121 Phone: 858-535-2030 Fax: 858-535-2035

Date: October 31, 2002

Contact Person: Edward Tung, Ph.D.

Product Name: ACON® Strep A Twist Rapid Test Device

Common Name:

Immunochromatographic test for the qualitative detection of Group A Streptococcal antigen from a throat swab specimen.

Device Classification:

The ACON Strep A Twist Rapid Test Device is similar to other FDA-cleared devices for the qualitative detection of Group A Streptococcus Antigen from throat swab specimens. These tests are used to aid in the diagnosis of Group A Streptococcus infection. (21 CFR 866.3740). Serological test systems for the detection of Group A Streptococcus antigen have been classified as Class I devices.

Classification Name:

Streptococcus spp. Serological reagents

Intended Use:

The ACON Strep A Twist Rapid Test Device is a rapid chromatographic immunoassay for the qualitative detection of Strep A antigen from throat swab specimens to aid in the diagnosis of Group A Streptococcal infection.

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Description:

Predicate Device:

Quidel QuickVue In-Line One-Step Strep A

510(k) Number K954257

Quidel Corp. 10165 McKellar Court San Diego, California 92121

Comparison to a Predicate Device:

A summary comparison of the features of the ACON Strep A Twist Rapid Test Device and the Quidel QuickVue In-Line One-Step Strep A is shown below.

Feature	ACON® Strep A Twist Rapid Test Device	QuickVue In-Line One-Step Strep A
Intended Use	A rapid chromatographic immunoassay for thequalitative detection of Strep antigens fromthroat swab specimens to aid in the diagnosisof Group A Streptococcal infection.	The QuickVue In-Line One-Step Strep Aallows for the rapid detection of group Astreptococcal antigen directly from patientthroat swabs. The test is intended to use as anaid in the diagnosis of group A streptococcalinfection.
Indications for Use	Professional & point of care use.	Professional & point of care use.
Intended Specimen	Throat Swab	Throat Swab
Endpoint	Colored Lines	Colored Lines
Materials Provided	Test DevicesSterile SwabsExtraction Reagents A & BPositive Control (Non-viable Strep A)Negative Control (Non-viable Strep C)Package InsertProcedure Card	Test CassettesSterile SwabsExtraction Solution bottlePositive Control (Heat-inactivated Strep A)Negative Control (Heat-inactivated Strep C)Package InsertProcedure CardExtraction kit for use with Proficiency Testingsamples only
Methodology	Membrane Particle Assay	Membrane Particle Assay
Extraction ReagentColor Reaction	Reagent A - Red ColorReagent B - Clear ColorCombined Reagents - Yellow color	Reagent inside bottle - Clear ColorReagent inside ampoule - Clear ColorCombined Reagents - Green color
Extraction Time	1 minute	up to 1 minute
Test Time	5 minutes	5 minutes
Format	Immunochemical, Strep A antigen /antibody,immunoassay principle	Immunochemical, Strep A antigen/antibody,immunoassay principle
Organism detection	Strep A specific	Strep A specific

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Safety and Effectiveness Data:

Accuracy

A multi-center clinical evaluation was conducted with specimens from 758 patients presenting with signs and symptoms of pharyngitis. This evaluation compared the result of the ACON® Strep A Twist Rapid Test Device and another commercially available Strep A test device, the QuickVue In-Line One-Step Strep A test to the customary Strep A confirmed culture technique.

In this study, there were a total of four invalid results, two with the Quidel product and two with the ACON product. These invalid results were excluded from the data analysis. The data from this study vielded the following results:

ACON Strep A Twist Rapid Test Device compared to QuickVue In-Line One-Step Strep A.

Positive Agreement: 130/138 = 94% (89-97)*
Negative Agreement: 375/375 = 100% (99-100)*
Overall Agreement: 505/513 = 98% (97-99)*

ACON Strep A Twist Rapid Test Device compared to Strep A confirmed Culture

Sensitivity:
Specificity:
Accuracy:

vice compared to Strep A confirmed C
240/265 = 90% (86-94)*
464/491 = 94% (92-96)*
704/756 = 93% (91-95)*

Denotes 95% confidence intervals

Sensitivity

Nine (9) different strains of Strep A were evaluated with the ACON Strep A Twist Rapid Test Device. The minimum detectable level differed slightly depending upon the strain being tested. The detection level of all of the strains was roughly within one magnitude in concentration of each other. Seven (7) strains showed a minimum detectable level at roughly 10° organisms per swab while two (2) strains showed a minimum detectable level at roughly 10 organisms per swab.

In addition, the throat swab specimens from the study that yielded beta-hemolytic colony growth were assigned a semi-quantitative value expressed as rare, 1+, 2+, 3+ or 4+. The ability of the ACON Strep A Twist Rapid Test Device to detect these various concentration levels is shown below.

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Culture Classification	ACON/Culture	% Correct
Negative (Specificity)	464/491	94%
Rare	4/11	36%
1+	16/20	80%
2+	17/23	74%
3+	26/29	90%
4+	175/182	96%
Total Positive (Sensitivity)	238/265	90%
Total (Overall Agreement)	702/756	93%

Specificity

Specificity studies were conducted by individually spiking the various bacterial strains listed below on swabs at a final concentration of 1.0 x 107 org/swab, then evaluating the swabs in duplicate according to the package insert. None of the organism demonstrated any cross-reactivity in the test. The organisms tested were:

Bordetella pertussis	Staphylococcus aureus
Branhamella catarrhalis	Staphylococcus epidermidis
Candida albicans	Strep B
Corynebacterium diphtheriae	Strep C
Enterococcus durans	Strep F
Enterococcus faecalis	Strep G
Hemophilus influenzae	Streptococcus mutans
Klebsiella pneumoniae	Streptococcus pneumoniae
Neisseria gonorrhea	Streptococcus sanguis
Neisseria meningitidis	Streptococcus intermedius
Neisseria sicca	Streptococcus oralis
Neisseria subflava	Streptococcus mitis
Pseudomonas aeruginosa	Streptococcus anginosus
Serratia marcescens	Escherichia coli

Interfering Substances

No interference to an expected negative or positive result was observed in our studies when using specimens containing the following substances at a final concentration of 1% (Mucin at 1 mg/swab):

Cherry Halls Cough Drops	Vicks Chloraseptic Spray
Menthol Halls Cough Drops	Cepacol Sore Throat Spray
Robitussin Cough Syrup	Listerine Mouthwash
Dimetapp Cough Elixir	Scope Mouthwash
Whole Blood at 100uL	Mucin (at 1 mg/swab)

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Intra and Inter-assay Variability

Studies to evaluate inter- and inter-assay variability demonstrated that the test yielded that expected results >99% of the time

Lot-to-Lot Variability

Studies to evaluate the manufacturability and consistency of the product on a lot-to-lot basis have shown this test to be highly reproducible.

Conclusion

These studies demonstrate the substantial equivalency of the ACON® Strep A Twist Rapid Test Device to the QuickVue In-Line One-Step Strep A, which is already marketed. They further demonstrate the suitability of this product for professional and point-of-care use, in addition to demonstrating its safety and effectiveness.

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Image /page/5/Picture/1 description: The image shows the logo for the U.S. Department of Health & Human Services. The logo consists of a circle with the text "DEPARTMENT OF HEALTH & HUMAN SERVICES - USA" around the perimeter. Inside the circle is a stylized image of three human profiles facing right, with flowing lines representing hair or clothing.

Food and Drug Administration 2098 Gaither Road Rockville MD 20850

FEB 1 0 2003

Edward Tung, Ph.D. Director of Regulatory Affairs Acon Laboratories, Inc. 4108 Sorrento Valley Boulevard San Diego, CA 92121

Re: K023766

Trade/Device Name: Acon® Strep A Twist Rapid Test Device Regulation Number: 21 CFR 866.3740 Regulation Name: Streptococcus Spp. Serological Reagents Regulatory Class: Class I Product Code: GTY Dated: November 8, 2002 Received: November 12, 2002

Dear Dr. Tung:

We have reviewed your Section 510(k) premarket notification of intent to market the device referenced above and have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to legally marketed predicate devices marketed in interstate commerce prior to May 28, 1976, the enactment date of the Medical Device Amendments, or to devices that have been reclassified in accordance with the provisions of the Federal Food. Drug, and Cosmetic Act (Act) that do not require approval of a premarket approval application (PMA). You may, therefore, market the device, subject to the general controls provisions of the Act. The general controls provisions of the Act include requirements for annual registration, listing of devices, good manufacturing practice, labeling, and prohibitions against misbranding and adulteration.

If vour device is classified (see above) into either class II (Special Controls) or class III (PMA), it may be subject to such additional controls. Existing major regulations affecting your device can be found in Title 21, Code of Federal Regulations (CFR), Parts 800 to 895. In addition, FDA may publish further announcements concerning your device in the Federal Register.

Please be advised that FDA's issuance of a substantial equivalence determination does not mean that FDA has made a determination that your device complies with other requirements of the Act or any Federal statutes and regulations administered by other Federal agencies. You must comply with all the Act's requirements, including, but not limited to: registration and listing (21 CFR Part 807); labeling (21 CFR Parts 801 and 809); and good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820).

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Page 2 -

This letter will allow you to begin marketing your device as described in your Section 510(k) premarket notification. The FDA finding of substantial equivalence of your device to a legally marketed predicate device results in a classification for your device and thus, permits your device to proceed to the market.

If you desire specific information about the application of labeling requirements to your device, or questions on the promotion and advertising of your device, please contact the Office of In Vitro Diagnostic Device Evaluation and Safety at (301) 594-3084. Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21CFR Part 807.97). Other general information on your responsibilities under the Act may be obtained from the Division of Small Manufacturers, International and Consumer Assistance at its toll-free number (800) 638-2041 or (301) 443-6597 or at its Internet address http://www.fda.gov/cdrh/dsma/dsmamain.html.

Sincerely yours,

Steven Sutman

Steven I. Gutman, M.D., M.B.A. Director Office of In Vitro Diagnostic Device Evaluation and Safety Center for Devices and Radiological Health

Enclosure

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INDICATIONS FOR USE 9.

510(k) Number:

K023766

Device Name:

The ACON® Strep A Twist Rapid Test Device

Indications For Use:

(Please do not write below this point) Concurrence of CDRH, Office of Device Evaluation (ODE)

Prescription Use_ レ

(Per 21 CFR 801.109)

Over-The-Counter Use

Freddie Jr. Pool.

(Division Sign-Off) Division of Clinical Laboratory Devices

510(k) Number KD23766

Regulation Number and Section

§ 866.3740

Streptococcus spp. serological reagents.(a)
Identification. Streptococcus spp. serological reagents are devices that consist of antigens and antisera (excluding streptococcal exoenzyme reagents made from enzymes secreted by streptococci) used in serological tests to identifyStreptococcus spp. from cultured isolates derived from clinical specimens. The identification aids in the diagnosis of diseases caused by bacteria belonging to the genusStreptococcus and provides epidemiological information on these diseases. Pathogenic streptococci are associated with infections, such as sore throat, impetigo (an infection characterized by small pustules on the skin), urinary tract infections, rheumatic fever, and kidney disease.(b)
Classification. Class I (general controls). The device is exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to § 866.9.