SAS LEGIONELLA TEST, SAS LEGIONELLA DIPSTICK TEST

K061496 · Sa Scientific , Ltd. · MJH · Jun 28, 2007 · Microbiology

Device Facts

• Record ID: K061496
• Device Name: SAS LEGIONELLA TEST, SAS LEGIONELLA DIPSTICK TEST
• Applicant: Sa Scientific , Ltd.
• Product Code: MJH · Microbiology
• Decision Date: Jun 28, 2007
• Decision: SESE
• Submission Type: Traditional
• Regulation: 21 CFR 866.3300
• Device Class: Class 2

Indications for Use

The SAS™ Legionella Test is a visually read, in vitro immunochromatographic rapid assay for the presumptive qualitative detection of Legionella pneumophila serogroup 1 antigens in human urine. This test is intended to aid in the presumptive diagnosis of Legionnaires’ disease in conjunction with culture and other methods for patients with signs and symptoms of pneumonia.

Device Story

SAS™ Legionella Test is a rapid, visually read, in vitro immunochromatographic assay. Input: human urine specimen. Principle: lateral flow immunoassay; urine migrates through sample pad to conjugate pad containing gold-conjugated antibodies specific to Legionella pneumophila antigens; if antigens present, 'half-sandwich' immunocomplex forms; complex migrates to nitrocellulose membrane with immobilized antibodies, forming 'whole sandwich' immunocomplex; visible pink line appears in specimen zone. Procedural control line appears in control zone regardless of antigen presence. Used in clinical settings; performed by healthcare professionals. Output: qualitative visual result (positive/negative). Aids in presumptive diagnosis of Legionnaires' disease in conjunction with culture and other clinical methods.

Clinical Evidence

Retrospective study of 324 frozen specimens compared SAS™ Legionella Cassette test against cell culture. Sensitivity: 90.5% (95% CI 83.2–95.3%); Specificity: 95.0% (95% CI 91.2–97.3%). Analytical specificity evaluated with 49 healthy patient urines (100% negative) and 99 urines from patients with other respiratory infections (99% negative). Reproducibility 100% across three sites.

Technological Characteristics

Immunochromatographic lateral flow assay; cassette format. Utilizes polyclonal antibodies against Legionella pneumophila antigens. Gold-conjugated antibody detection system. Nitrocellulose membrane with immobilized antibodies. Visual readout. No electronic components or software.

Indications for Use

Indicated for presumptive qualitative detection of Legionella pneumophila serogroup 1 antigens in human urine for patients with signs and symptoms of pneumonia to aid in the diagnosis of Legionnaires' disease.

Regulatory Classification

Identification

Haemophilus spp. serological reagents are devices that consist of antigens and antisera, including antisera conjugated with a fluorescent dye, that are used in serological tests to identify Haemophilus spp. directly from clinical specimens or tissue culture isolates derived from clinical specimens. The identification aids in the diagnosis of diseases caused by bacteria belonging to the genus Haemophilus and provides epidemiological information on diseases cause by these microorganisms. Diseases most often caused by Haemophilus spp. include pneumonia, pharyngitis, sinusitis, vaginitis, chancroid venereal disease, and a contagious form of conjunctivitis (inflammation of eyelid membranes).

Special Controls

*Classification.* Class II (special controls). The device is exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to § 866.9.

Predicate Devices

• Binax™ Now® Legionella Urinary Antigen Test

Submission Summary (Full Text)

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# 510(k) SUBSTANTIAL EQUIVALENCE DETERMINATION DECISION SUMMARY

A. 510(k) Number:
K061496

B. Purpose for Submission:
New device

C. Measurand:
Legionella pneumophila serogroup 1 antigens

D. Type of Test:
Immunochromatographic rapid assay

E. Applicant:
SA Scientific, Ltd.

F. Proprietary and Established Names:
SAS™ Legionella Test

G. Regulatory Information:
1. Regulation section: 21CFR 866.3300, Haemophilus spp. Serological Reagents
2. Classification: Class: II
3. Product code: MJH: Legionella, spp., ELISA
4. Panel: 83 Microbiology

H. Intended Use:
The SAS™ Legionella Test is a visually read, in vitro immunochromatographic rapid assay for the presumptive qualitative detection of Legionella pneumophila serogroup 1 antigens in human urine. This test is intended to aid in the presumptive diagnosis of Legionnaires’ disease in conjunction with culture and other methods for patients with signs and symptoms of pneumonia.

2. Indication(s) for use:
The SAS™ Legionella Test is a visually read, in vitro immunochromatographic rapid assay for the presumptive qualitative detection of Legionella pneumophila serogroup

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1 antigens in human urine. This test is intended to aid in the presumptive diagnosis of Legionnaires' disease in conjunction with culture and other methods for patients with signs and symptoms of pneumonia.

3. Special conditions for use statement(s):

For prescription use only

4. Special instrument requirements:

None

I. Device Description:

The SAS™ Legionella test utilizes a combination of polyclonal antibodies against the antigens of Legionella pneumophila. The SAS™ Legionella test begins with the addition of urine to the test device. The specimen is absorbed by the sample pad and then moves through the conjugate pad which contains dried gold conjugated antibodies which are specific for Legionella pneumophila antigens; if the Legionella antigens are present in the urine sample, a "half-sandwich" immunocomplex is formed. This immuno-complex then migrates via capillary action along a nitrocellulose membrane containing immobilized antibodies to Legionella pneumophila antigens. The immobilized antibodies bind the "half-sandwich" immuno-complex to form a "whole sandwich" immuno-complex. Thus, when the "whole sandwich" is formed, a visible, pink colored line develops in the specimen zone on the test device. In the absence of a Legionella antigen, a "sandwich" immuno-complex is not formed and a negative result is indicated. To serve as a procedural control, a pink colored control line will always appear in the control zone regardless of the presence or absence of Legionella antigen. The test is in a cassette format.

J. Substantial Equivalence Information:

1. Predicate device name(s): Binax™ Now® Legionella Urinary Antigen Test
2. Predicate 510(k) number(s): K982238
3. Comparison with predicate:

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| Similarities | | |
| --- | --- | --- |
| Item | Device | Predicate |
| Specimen Type | Human urine | Human urine |
| Method and type | Qualitative | Qualitative |
| | Immunochromatography | Immunochromatography |
| Antigen detected | L. pneumophila serogroup 1 | L. pneumophila serogroup 1 |
| Differences | | |
| Item | Device | Predicate |
| Sample application | Direct urine | Urine in swab |

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

Not applicable

# L. Test Principle:

Immunochromatography

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

# 1. Analytical performance:

a. Precision/Reproducibility:

The reproducibility of the $\mathrm{SAS^{TM}}$ Legionella Test was evaluated at three clinical laboratory sites. The $\mathrm{SAS^{TM}}$ Legionella Test was tested against a panel of six (6) specimens of which included four levels of positives and two negatives. The low and high positives were from the purified Legionella antigen. Negative were comprised of either urine or Legionella antigen below the detectable limit. Three (3) different laboratory personnel assayed each specimen at each laboratory facility over 3 days. The overall reproducibility for the $\mathrm{SAS^{TM}}$ Legionella Test was $100\%$ .

b. Linearity/assay reportable range:

Not applicable

c. Traceability, Stability, Expected values (controls, calibrators, or methods):

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Not applicable

d. Detection limit:

The limit of detection of the SAS™ Legionella test was determined to be 5 x 10⁴. Legionella pneumophila serogroup 1 ATCC 323152 was prepared using BCYE agar. A dilution of the working concentration was performed. The limit of detection of the SAS™ Legionella Cassette Test was determined from these concentrations.

e. Analytical specificity:

Analytical Specificity: Forty-Nine (49) fresh patient urines from healthy individuals were collected prospectively and assayed at a clinical site. One hundred percent (100%) of these were found to be negative by the SAS™ Legionella test.

Ninety-nine (99) urines from patients diagnosed for other etiological respiratory tract infections (84 culture confirmed, 15 suspected) were tested using the SAS™ Legionella Test. The results showed a lack of reactivity in 98/99 samples (99.0%).

Bacterial Cross-Reactivity: To confirm the analytical specificity of the SAS™ Legionella Test, bacterial cultures likely to be found in the respiratory tract were tested. All yielded negative results. To confirm a lack of interference by other bacterial species in the SAS™ Legionella Test, purified Legionella antigen was added to bacterial cultures likely to be found in the respiratory tract. All tests yielded positive results.

f. Assay cut-off:

Not applicable

2. Comparison studies:

a. Method comparison with predicate device:

Clinical Sensitivity and Specificity: Three clinical sites (USA and Netherlands) tested three hundred twenty four (324) retrospective frozen specimens using the SAS™ Legionella Cassette test. These samples were previously tested for Legionella by cell culture.

Sensitivity: 95/105 x 100 = 90.5 % (95% CI 83.2 – 95.3%)

Specificity: 208/219 x 100 = 95.0 % (95% CI 91.2 – 97.3%)

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b. Matrix comparison:
Not applicable

3. Clinical studies:
a. Clinical Sensitivity:
Not applicable
b. Clinical specificity:
Not applicable
c. Other clinical supportive data (when a. and b. are not applicable):
Not applicable

4. Clinical cut-off:
Not applicable

5. Expected values/Reference range:
Not applicable

N. Proposed Labeling:
The labeling is sufficient and it satisfies the requirements of 21 CFR Part 809.10.

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