← Product Code [GNA](/submissions/MI/subpart-d%E2%80%94serological-reagents/GNA) · K031367

# DUOPATH VEROTOXINS GLISA TEST (K031367)

_Emd Chemicals, Inc. · GNA · Jan 23, 2004 · Microbiology · SESE_

**Canonical URL:** https://fda.innolitics.com/submissions/MI/subpart-d%E2%80%94serological-reagents/GNA/K031367

## Device Facts

- **Applicant:** Emd Chemicals, Inc.
- **Product Code:** [GNA](/submissions/MI/subpart-d%E2%80%94serological-reagents/GNA.md)
- **Decision Date:** Jan 23, 2004
- **Decision:** SESE
- **Submission Type:** Traditional
- **Regulation:** 21 CFR 866.3255
- **Device Class:** Class 1
- **Review Panel:** Microbiology

## Indications for Use

The Duopath® Verotoxins GLISA test is a rapid test for the qualitative identification of Verotoxins I and II produced by E. coli isolated in cultures. The test aids in the diagnosis of diseases caused by enterohemorrhagic E. coli infections.

## Device Story

Immunochromatographic rapid test (GLISA) for qualitative detection of Verotoxins I and II from bacterial culture isolates. Input: bacterial culture sample applied to port. Operation: gold-labeled monoclonal antibodies bind verotoxins; complex migrates chromatographically along cellulose nitrate membrane; binds to immobilized monoclonal antibodies. Output: visual red line in test window (VT1, VT2) indicates presence of toxin; red line in control window confirms proper wicking. Used in clinical laboratory settings. Results interpreted visually by laboratory personnel to aid diagnosis of enterohemorrhagic E. coli infections.

## Clinical Evidence

No clinical data provided; device is a serological reagent test for in vitro diagnostic use.

## Technological Characteristics

Lateral flow immunochromatographic assay; qualitative detection of Verotoxins I and II; in vitro diagnostic reagent; manual test format.

## Regulatory Identification

Escherichia coli serological reagents are devices that consist of antigens and antisera used in serological tests to identify Escherichia coli from cultured isolates derived from clinical specimens. Additionally, some of these reagents consist of Escherichia coli antisera conjugated with a fluorescent dye used to identify Escherichia coli directly from clinical specimens or cultured isolates derived from clinical specimens. The identification aids in the diagnosis of diseases caused by this bacterium belonging to the genus Escherichia, and provides epidemiological information on diseases caused by this microorganism. Although Escherichia coli constitutes the greater part of the microorganisms found in the intestinal tract in humans and is usually nonpathogenic, those strains which are pathogenic may cause urinary tract infections or epidemic diarrheal disease, especially in children.

## Submission Summary (Full Text)

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

A. 510(k) Number: K031367
B. Analyte: Escherichia coli
C. Type of Test: Qualitative, immunochromatographic rapid test
D. Applicant: EMD Chemicals, Inc.
E. Proprietary and Established Names: Duopath® Verotoxins GLISA Test

F. Regulatory Information:
1. Regulation section: Escherichia coli serological regents, 21 CFR 866.3255
2. Classification: Class I
3. Product code: GNA
4. Panel: Microbiology (83)

G. Intended Use and Indication for Use:
1. Intended use(s): In vitro diagnostic test for qualitative detection of verotoxins (Shiga-like toxins[SLT] I and II from E. coli
1. Indication(s) for use: The Duopath® Verotoxins GLISA test is a rapid test for the qualitative identification of Verotoxins I and II (Shiga-like toxins) produced by E. coli isolated in cultures derived from clinical specimens. The identification aids in the diagnosis of diseases caused by enterohemorrhagic E. coli infections.

H. Device Description: Duopath Verotoxin is an immunochromatographic rapid test based on the GLISA method (Gold-labeled Immunosorbent Assay). Duopath Verotoxin enables the detection of verotoxin (synonymous: Shiga-like toxins, SLT's) variants I and II from bacterial culture isolates. The test device has a circular sample port, and an oval shaped test (VT1, VT2) and control © window. The device includes a highly specific gold-marked monoclonal antibodies, which can bind verotoxin I and II upon application of verotoxin-containing sample material to the sample port.

I. Substantial Equivalence Information:
1. Predicate device name(s): Meridian Premier EHEC
2. Predicate K number(s): K950167 and K953362

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3. Comparison with predicate:

|  Similarities  |   |   |
| --- | --- | --- |
|  Item | Device | Predicate  |
|  1. Intended Use | Detection of verotoxins (Shiga-like toxins[SLT] I and II from E.coli | Detection of verotoxins (Shiga-like toxins[SLT] I and II from E.coli  |
|  2. Configuration | ELISA (enzyme-linked Immunosorbent assay) in which the antigen is embedded between a capture antibody and a detection antibody and incorporates monoclonal antibodies. Specific for Verotoxin I and II. | ELISA (enzyme-linked Immunosorbent assay) in which the antigen is embedded between a capture antibody and a detection antibody and incorporates monoclonal antibodies. Specific for Verotoxin I and II.  |
|  3. Sample | Stool | Stool  |
|  Differences  |   |   |
|  Item | Device | Predicate  |
|  1. Type | Lateral flow immunochromatographic rapid test based on gold-labeled antibodies. | ELISA  |
|  2. Antibody | Immobilized and dried on the surface of gold particles. | Immobilized and dried in a polystyrene surface.  |
|  3. Color Reaction | Mediated by the red color of the gold particles | Mediated by the peroxidase enzyme  |
|  4. Test Time | 20 minutes | 3 to 5 hours  |

# J. Standard/Guidance Document Referenced : Not Applicable

K. Test Principle: The Duopath® Verotoxin uses GLISA (gold labeled immunosorbent assay) methodology. GLISA uses monoclonal antibodies immobilized on gold particles. The gold-labeled monoclonal antibodies flow in complexes with the verotoxin over a cellulose nitrate membrane and attach to immobilized monoclonal antibodies, which are also highly specific for the verotoxin I and verotoxin II on the membrane. The sample reacts with gold coated particles that have been applied to the label pad. This mixture migrates chromatographically along the length of the test strip and interacts with the immobilized monoclonal antibodies. If the sample contains verotoxin, a colored line will appear in the test line region and control position indicating a positive result. If the sample does not contain verotoxin, a red colored line will only appear in the control region indicating a negative result. To serve as a procedural control, a red colored line will always appear at the control line region, indicating that proper volume of specimen has been added and membrane wicking has occurred.

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L. Performance Characteristics :

1. Analytical performance:

a. Precision/Reproducibility: Reproducibility studies evaluated inter-lot, inter/intra-site and inter-laboratory variability. Assay performance was evaluated by testing 9 specimens three times over three days at three sites. Samples consisted of three negative, three low positives and three strong positives. The result of combined with-in run and total imprecision are shown within the package insert. Results were presented according to the NCCLS standards.

b. Linearity/assay reportable range: Not Applicable

c. Traceability, Calibrators, and Controls: Not Applicable

d. Analytical sensitivity: The lower limits of detection were calculated as 25 ng/mL for VT1 and 62.5 ng/mL for VT2. Solutions containing verotoxins 1 and 2 were mixed 1 + 1 and applied onto the Duopath assay. Parallel testing was performed on 4 production batches and the results were reported as dose response.

e. Analytical specificity: There was no cross-reactivity when a variety of organisms, which included Pseudomonas, Klebsiella, Enterobacter, Salmonella, and Shigella, were tested with the Duopath® Verotoxin assay. The methodology used for the cross-reactivity study did not allow a determination for the numerical concentration of the potentially cross-reactive organisms. Organisms were inoculated onto Sorbitol-Mackey (SMAC) agar. The inoculum was prepared using a Dacron swab which was swept across the areas of growth on the plates. The swabs were incubated in appropriate media (18/24 hr for EHEC) or in distilled water treated with polymyxin B (30 minutes for Duopath®). The number of isolates tested and results are listed below.

|  Organism | No. isolates tested | EHEC | Duopath  |
| --- | --- | --- | --- |
|  Ps. Aeruginosa | 10 | Negative | Negative  |
|  K. pneumoniae | 10 | Negative | Negative  |
|  Enterobacter sp. | 10 | Negative | Negative  |
|  Proteus sp. | 10 | Negative | Negative  |
|  Aeromonas sp. | 3 | Negative | Negative  |
|  Serratia sp. | 5 | Negative | Negative  |
|  Shigella sp. | 3 | Negative | Negative  |
|  Salmonella | 7 | Negative | Negative  |

f. Analytical characterization of cut-off: Assay cut-off was determined by reading against a color intensity chart. The intensity of the color on the device was compared to the chart and scored using a scale from 0 – 10.

2. Comparison studies using clinical specimens:

Method comparison: Two hundred ninety retrospective and prospective stool specimens were evaluated with the Duopath® Verotoxin and the Premier™ EHEC assays. Of the 290, 41 were retrospective and 249 were prospective specimens. Results were reported as 100% positive agreement for the retrospective study, and 100% positive agreement and 99.6% negative agreement

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with the prospective study. The firm reported no false positive result and one false negative result.

|  DUOPATH® | VEROTOXIN
Fresh Specimen  |   |   |
| --- | --- | --- | --- |
|   | Positive | Negative | Totals  |
|  REFERENCE METHOD* |  |  |   |
|  Positive | 5 | 0 | 5  |
|  Negative | 1 | 243 | 244  |
|  Totals | 6 | 243 | 249  |
|  % agreement + | 100% | 5/5 |   |
|  % agreement - | 99.6% | 243/244 |   |
|  DUOPATH®  |   |   |   |
| --- | --- | --- | --- |
|   | VEROTOXIN
Frozen Specimen  |   |   |
|   | Positive | Negative | Totals  |
|  REFERENCE METHOD* |  |  |   |
|  Positive | 41 | 0 | 41  |
|  Negative | 0 | 0 | 0  |
|  Totals | 41 | 0 | 41  |
|  % agreement + | 100% | 41/41 |   |
|  % agreement - | No Negative Results |   |   |

a. Matrix description and comparison: Not Applicable

M. Conclusion: Performance demonstrated that the Duopath® Verotoxin GLISA assay to be substantially equivalent to other legally marketed devices performing the same testing.

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**Source:** [https://fda.innolitics.com/submissions/MI/subpart-d%E2%80%94serological-reagents/GNA/K031367](https://fda.innolitics.com/submissions/MI/subpart-d%E2%80%94serological-reagents/GNA/K031367)

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