STATUS FIRST STREP A

K040708 · Princeton BioMeditech Corp. · GTY · Nov 22, 2004 · Microbiology

Device Facts

• Record ID: K040708
• Device Name: STATUS FIRST STREP A
• Applicant: Princeton BioMeditech Corp.
• Product Code: GTY · Microbiology
• Decision Date: Nov 22, 2004
• Decision: SESE
• Submission Type: Traditional
• Regulation: 21 CFR 866.3740
• Device Class: Class 1
• Attributes: Pediatric

Indications for Use

Status First™ Strep A is an immunoassay for the qualitative detection of Group A Streptococcal antigen directly from throat swab specimens to aid in the early diagnosis of Group A Streptococcal infection.

Device Story

Status First™ Strep A is an in vitro, one-step immunochromatographic diagnostic test. It detects Group A Streptococcal antigen directly from throat swab specimens. The device functions as a rapid, qualitative immunoassay. It is intended to aid healthcare providers in the early diagnosis of Group A Streptococcal infection. The test provides a visual result, allowing for immediate clinical assessment and decision-making regarding patient treatment.

Clinical Evidence

No clinical data provided; substantial equivalence is based on technological and performance similarity to the predicate device.

Technological Characteristics

In vitro immunochromatographic assay. One-step qualitative test format. Designed for use with throat swab specimens.

Indications for Use

Indicated for qualitative detection of Group A Streptococcal antigen in throat swab specimens to aid in early diagnosis of Group A Streptococcal infection.

Regulatory Classification

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 identify Streptococcus spp. from cultured isolates derived from clinical specimens. The identification aids in the diagnosis of diseases caused by bacteria belonging to the genus Streptococcus 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.

Predicate Devices

• BioSign™Strep A (K971349)

Submission Summary (Full Text)

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510(k) SUBSTANTIAL EQUIVALENCE DETERMINATION
DECISION SUMMARY
DEVICE ONLY TEMPLATE

A. 510(k) Number:
K040708

B. Purpose of Submission:
For the modification of their previously approved device

C. Analyte:
Group A Streptococcal antigen

D. Type of Test:
Horizontal-flow enzyme immunoassay

E. Applicant:
Princeton BioMeditech Corporation

F. Proprietary and Established Names:
Status First™ Strep A

G. Regulatory Information:
1. Regulation section:
21 CFR Part 866.3740 Streptococcus spp. serological reagents
Limitation: 21 CFR 866.9 (6)
2. Classification:
I
3. Product Code:
GTY – Streptococcus spp.
4. Panel:
83 Microbiology

H. Intended Use:
1. Intended use(s):
Status First™ Strep A is a rapid immunochromatographic assay for the qualitative detection of group A streptococcal antigen directly from throat swab specimens. The test is intended for use as an aid in the early diagnosis of group A streptococcal infection.
2. Indication(s) for use:
Status First™ Strep A is an immunoassay for the qualitative detection of Group A Streptococcal antigen directly from throat swab specimens to aid in the early diagnosis of Group A Streptococcal infection.
3. Special condition for use statement(s):
For Prescription Use Only

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4. Special instrument Requirements:
Not applicable

I. Device Description:
The device consists of a chromatography strip membrane housed in a plastic frame. The membrane carries immobilized polyclonal anti-Strep A antibody coupled to colloidal gold dye particles. The test line contains rabbit anti-group A streptococcus antibody. The control line consists of an immobilized antibody to the anti-Strep A indicator antibody. At the control line, anti-Strep A indicator antibody-unbound/bound colloidal gold complexes form a control line in the control window which indicates that the device is functioning properly.

J. Substantial Equivalence Information:
1. Predicate device name(s):
BioSign™Strep A
2. Predicate K number(s):
K971349
3. Comparison with predicate(s):

| Similarities | | |
| --- | --- | --- |
| Item | Device | Predicate |
| Intended use | For the qualitative detection of group A streptococcal antigen directly from throat swabs. | same |
| Specimen type | Throat swab | same |
| technology | Immunochromatographic | same |
| antibodies | Polyclonal anti-Strep A | same |
| Limit of detection | 1.5x10^{5} cfu/ml | same |
| Clinical sensitivity | 96.2% CI (%) | same |
| Clinical specificity | 98.7% CI (%) | same |
| | Difference | |
| Item | Device | Predicate |
| Extraction method | Extraction step performed within the test device | Extraction performed in a test tube and transferred to test device |

The performance of Status First™ Strep A was validated by conducting comparison studies with the BioSign™ Strep A to demonstrate that performance of the assay was not altered by this modification. The firm performed time, readability, and sensitivity evaluations. A total of 120 devices were tested with negative, low (1.5 x 10⁵ cfu/ml), and medium (1.2 x 10⁶ cfu/ml) levels of Strep A antigen according to the test protocol in each package insert. The test signals of both tests were read at 5 minutes after sample application on the test strip. No differences were observed between Status First™ Strep A and BioSign™ Strep A in the sensitivity, readability and assay time.

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## K. Standard/Guidance Document referenced (if applicable):

Not applicable

## L. Test Principle:

Status First™ Strep A is a rapid immunochromatographic assay for the qualitative detection of group A streptococcal antigen directly from throat swab specimens. The test involves the chemical extraction of Group A streptococcal antigen utilizing solid-phase immunoassay technology for the detection of extracted antigen. In the test procedure, a throat swab specimen is collected and placed into a mixture of Reagents A and B that have been added to the extraction well of the device. If group A Streptococci is present in the specimen, it will react with anti-Strep A indicator antibody coupled to colloidal gold particles. The mixture will migrate through the membrane as antigen-antibody-gold complexes and bind to the immobilized polyclonal anti-Strep A antibody on the membrane to generate a colored line in the Test Window. The rest of the sample and unbound/bound colloidal gold complexes continues to migrate to the control line where antibody to the anti-Strep A indicator antibody is immobilized. At the Control line, anti-Strep A indicator antibody-unbound/bound colloidal gold complexes form a control line in the Control Window. The presence of two colored lines, one in the Test window and the other in the Control window indicates a positive result. Alternatively, a negative result is described as no line forming in the test window but a line forms in the Control window.

## M. Performance Characteristics (if/when applicable):

### 1. Analytical performance:

a. Precision/Reproducibility:

The reproducibility was determined using the new test device Status First™ Strep A test. The device was evaluated at three sites by three operators for three days testing 15 blind samples per person per day. The 15 samples consisted of 5 negative samples, 5 low positive samples containing approximately $3 \times 10^{5}$ cfu/ml, and 5 medium positive samples containing approximately $1.2 \times 10^{6}$ cfu/ml. The samples were prepared from known live cultures of ATCC strain 19615. The samples were provided in each vial with number coding for the blind testing. The test results by 9 operators from three sites for three days (total of 135 tests per site) showed complete agreement (100%).

b. Linearity/assay reportable range:

Not applicable

c. Traceability (controls, calibrators, or method):

Not applicable

d. Detection limit:

The minimum detectability of the test is $1.5 \times 10^{5}$ cfu/ml that was established by testing a known number of organisms, (ATCC 14285 or ATCC 19615) using Todd Hewitt Broth. The culture organisms were serially diluted in culture medium and tested by BioSign™ Strep A.

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The same dilutions were cultured overnight on sheep blood agar plates for cell enumeration in cfu/ml.

e. Analytical specificity:

The analytical specificity using the predicate BioSign™Strep A device were accepted. No additional studies were required. In that study, organisms expected to be found in the respiratory tract were tested at a final concentration of 1 x 10⁷ organisms per mL. The organisms were tested alone in the device as well as spiked with a positive Strep A control (3 x 10⁵ cfu/ml) to confirm the test results. The results were all negative which confirmed that none of the microbial agents tested reacted with the device.

No interference study was conducted with the previously approved device or new device.

f. Assay cut-off

The assay was determined to detect 1.5 x 10⁵ cfu/ml.

2. Comparison studies:

a. Method comparison with gold standard: Not applicable
b. Matrix comparison: Not applicable

3. Clinical studies:

a. Clinical sensitivity:

The original performance studies using the BioSign™ Strep A were accepted for this modified device. The predicate device was compared to conventional plate culture techniques in a prospective evaluation of clinical specimens. Throat swab specimens were collected from 505 children and adult patients with pharyngitis symptoms. The results of the parallel tests are given below.

| | | BioSign™ Strep A | | |
| --- | --- | --- | --- | --- |
| | | Pos | Neg | Total |
| Confirmed 18/48 hours (+) | | 127 | 5 | 132 |
| Culture Results (-) | | 5 | 368 | 373 |
| Total | | 132 | 373 | 505 |
| | | | | 95% CI |
| Clinical sensitivity | 127/132 (96.2%) | | | 95-98.9% |
| Clinical specificity | 368/372 (98.7%) | | | 98-100% |

b. Clinical specificity:

Refer to (a.) above

c. Other clinical supportive data (when a and b is not applicable):

Not applicable

4. Clinical cut-off:

The lower limit of detection of this assay is 1.5 x 10⁵ cfu/ml.

5. Expected values/Reference range: (Interpretive Criteria)

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Group A Streptococcus infection exhibits a seasonal variation and is most prevalent in the winter and early spring. Approximately 19% of all upper respiratory tract infection are caused by group A Streptococcus. The highest incidence of this disease is found in high density populations, such as school aged children and military bases. Males and females are equally affected by the disease.

**N. Conclusion:**

The submitted information in this premarket notification is complete and supports a substantial equivalence decision.