YEAST TRAFFIC LIGHT PNA FISH

K093024 · Advandx, Inc. · NZS · Jul 15, 2010 · Microbiology

Device Facts

• Record ID: K093024
• Device Name: YEAST TRAFFIC LIGHT PNA FISH
• Applicant: Advandx, Inc.
• Product Code: NZS · Microbiology
• Decision Date: Jul 15, 2010
• Decision: SESE
• Submission Type: Traditional
• Regulation: 21 CFR 866.2660
• Device Class: Class 1

Indications for Use

Yeast Traffic Light PNA FISH is a multicolor, qualitative nucleic acid hybridization assay intended for the identification of Candida albicans and/or Candida parapsilosis, identification of Candida tropicalis, and identification of Candida glabrata and/or Candida krusei on smears made from positive blood cultures containing yeasts observed on Gram stain or other microbiological stains. The test does not distinguish between C. albicans and C. parapsilosis. The test does not distinguish between C. qlabrata and C. krusei. Subculturing of positive blood cultures is necessary to recover organisms for susceptibility testing, differentiation between C. albicans and C. parapsilosis, differentiation between C. glabrata and C. krusei, and/or differentiation of mixed growth. Yeast Traffic Light PNA FISH is indicated for use as an aid in the diagnosis of C. albicans and/or C. parapsilosis, C. tropicalis, and C. glabrata and/or C. krusei fungemia.

Device Story

Yeast Traffic Light PNA FISH is a qualitative nucleic acid hybridization assay; utilizes Peptide Nucleic Acid (PNA) probes for identification of specific Candida species in positive blood culture smears. Input: smears from positive blood cultures containing yeast. Process: multicolor fluorescence in situ hybridization (FISH) allows visual identification of Candida groups based on fluorescent color patterns. Output: qualitative identification of C. albicans/C. parapsilosis (green), C. tropicalis (red), and C. glabrata/C. krusei (yellow). Used in clinical microbiology laboratories by trained technicians. Results aid clinicians in rapid diagnosis of fungemia, facilitating earlier targeted antifungal therapy. Requires subculturing for susceptibility testing and further species differentiation.

Clinical Evidence

No clinical data provided in the summary document; device evaluation relies on performance characteristics of the PNA FISH assay for identification of Candida species from positive blood culture smears.

Technological Characteristics

Multicolor qualitative nucleic acid hybridization assay; utilizes Peptide Nucleic Acid (PNA) probes; fluorescence in situ hybridization (FISH) principle; visual detection via fluorescence microscopy; provides identification of Candida species groups based on specific fluorescent color signals.

Indications for Use

Indicated for patients with yeast-positive blood cultures (observed via Gram stain or other microbiological stains) to aid in the diagnosis of Candida tropicalis, Candida albicans, Candida parapsilosis, Candida glabrata, and Candida krusei fungemia.

Regulatory Classification

Identification

A microorganism differentiation and identification device is a device intended for medical purposes that consists of one or more components, such as differential culture media, biochemical reagents, and paper discs or paper strips impregnated with test reagents, that are usually contained in individual compartments and used to differentiate and identify selected microorganisms. The device aids in the diagnosis of disease.

Submission Summary (Full Text)

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

A. 510(k) Number:
K093024

B. Purpose for Submission:
To obtain a SE determination for a modification of the assay procedure for Yeast Traffic Light PNA FISH; the specific modifications are: elimination of the 5-10 minutes ethanol step in smear preparation; a reduction of the hybridization time from 90 minutes to 30 minutes.

C. Measurand:
Candida tropicalis, Candida albicans and Candida parapsilosis, Candida glabrata and Candida krusei specific ribosomal RNA sequences

D. Type of Test:
Fluorescence In Situ Hybridization (FISH) using protein nucleic acid (PNA) probes

E. Applicant:
AdvanDx, Inc

F. Proprietary and Established Names:
AdvanDx Yeast Traffic Light PNA FISH Culture Identification Kit

G. Regulatory Information:
1. Regulation section:
866.2660
2. Classification:
Class I
3. Product code:
NZS

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4. Panel:

83 Microbiology

H. Intended Use:

1. Intended use(s):

Yeast Traffic Light PNA FISH is a multicolor, qualitative nucleic acid hybridization assay intended for the identification of Candida albicans and/or Candida parapsilosis, identification of Candida tropicalis, and identification of Candida glabrata and/or Candida krusei on smears made from positive blood cultures containing yeasts observed on Gram stain or other microbiological stains. The test does not distinguish between C. albicans and C. parapsilosis. The test does not distinguish between C. glabrata and C. krusei.

Subculturing of positive blood cultures is necessary to recover organisms for susceptibility testing, differentiation between C. albicans and C. parapsilosis, differentiation between C. glabrata and C. krusei, and/or differentiation of mixed growth.

Yeast Traffic Light PNA FISH is indicated as an aid in the diagnosis of Candida tropicalis, Candida albicans and Candida parapsilosis, and Candida glabrata and Candida krusei fungemia.

2. Indication(s) for use:

Yeast Traffic Light PNA FISH is a multicolor, qualitative nucleic acid hybridization assay intended for the identification of Candida albicans and/or Candida parapsilosis, identification of Candida tropicalis, and identification of Candida glabrata and/or Candida krusei on smears made from positive blood cultures containing yeasts observed on Gram stain or other microbiological stains. The test does not distinguish between C. albicans and C. parapsilosis. The test does not distinguish between C. glabrata and C. krusei.

Subculturing of positive blood cultures is necessary to recover organisms for susceptibility testing, differentiation between C. albicans and C. parapsilosis, differentiation between C. glabrata and C. krusei, and/or differentiation of mixed growth.

Yeast Traffic Light PNA FISH is indicated as an aid in the diagnosis of Candida tropicalis, Candida albicans and Candida parapsilosis, and Candida glabrata and Candida krusei fungemia.

3. Special conditions for use statement(s):

Prescription use only

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4. Special instrument requirements:

Dual Band Filter (Cat. No. AC003)

Microscope Slides (Cat. No. AC001)

I. Device Description:

Yeast Traffic Light PNA FISH is a fluorescence in situ hybridization (FISH) method using PNA probes hybridizing to specific ribosomal RNA sequences of Candida albicans, C. parapsilosis, C. glabrata, C. krusei, and C. tropicalis. The test provides rapid identification of C. albicans + C. parapsilosis, C. tropicalis, and C. glabrata + C. krusei on smears made from yeast positive blood cultures within 90 minutes.

The PNA FISH technology in the Yeast Traffic Light PNA FISH (new) is similar to the technology used for Yeast Traffic Light PNA FISH (k080719) differing only in the elimination of the ethanol step in the sample preparation and the reduction of hybridization time from 90 to 30 minutes.

J. Substantial Equivalence Information:

1. Predicate device name(s):

Yeast Traffic Light PNA FISH

2. Predicate 510(k) number(s):

K080719

3. Comparison with predicate:

| Similarities | | |
| --- | --- | --- |
| Item | Device | Predicate |
| Technology | Fluorescence In Situ Hybridization (FISH) using protein nucleic acid (PNA) probe | Same |
| Sample | Positive blood culture | Same |
| PNA Probes | C. albicans PNA/Flu C. parapsilosis PNA/Flu C. tropicalis PNA/Flu C. tropicalis PNA/Tam C. glabrata PNA/Tam C. krusei PNA/Tam | Same |
| Differences | | |
| --- | --- | --- |
| Item | Device | Predicate |
| Fixed smear treatment | None | Ethanol for 10 minutes and air dried |
| Hybridization at 55°C | 30 minutes | 90 minutes |

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

Non applicable

L. Test Principle:

A mixture of fluorophore-labeled PNA probes is added to a smear prepared from a culture. Hybridization is performed at 55°C for 30 minutes. The hybridization is followed by a post-hybridization wash at 55°C for 30 min. with a stringent Wash Solution to remove unbound PNA probe, then the smear is mounted with Mounting Medium and examined by fluorescence microscopy.

The C. albicans-specific PNA probe and the C. parapsilosis-specific PNA probe are labeled with fluorescein (green). Both the C. albicans and the C. parapsilosis are identified as green fluorescent cells. The test does not distinguish between C. albicans and the C. parapsilosis.

Two C. tropicalis-specific PNA probes of the same sequence are labeled with fluorescein (green) and rhodamine (red), respectively. C. tropicalis is identified by combined read and green fluorescent probes binding in cells which then appear yellow by using the dual band filter.

The C. glabrata-specific PNA probe and the C. krusei-specific PNA probe are labeled with rhodamine (red). C. glabrata and C. krusei are identified as red fluorescent cells. The test does not distinguish between C. glabrata and the C. krusei.

M. Performance Characteristics (if/when applicable):

1. Analytical performance:

a. Precision/Reproducibility:

The assay was performed on 13 slides (19 isolates) in triplicate on three separate days at three separate sites. Each batch was run independently by at least two different operators at each site. The reproducibility was >95%.

b. Linearity/assay reportable range:

Not applicable

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

Positive Control:

C. albicans ATCC 18804 Green
C. glabrata ATCC 2001 Red
C. tropicalis ATCC 750 Yellow

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# Negative Control:
*S. cerevisiae* ATCC 18824
Negative

All results were as expected.

## d. Detection limit:

The detection limit was determined to be approximately $10^{5}$ CFU/mL by serial dilutions of *C. tropicalis*, *C. albicans*, *C. parapsilosis*, *C. glabrata* and *C. krusei* cultures. The average number of colonies per mL (CFU/mL) was calculated from three plates. The data sets showed a minimum of $10^{5}$ CFU/mL to produce a positive result for the Yeast Traffic Light PNA FISH™ assay.

## e. Analytical specificity:

Yeast Traffic Light PNA FISH has been evaluated on 75 laboratory and reference strains comprising *Candida* species and other closely related yeasts species and a variety of other frequently isolated organisms. The results demonstrated:

All (10/10) *C. albicans*, including two *C. stellatoidae* (a variant of *C. albicans*), and (4/4) *C. parapsilosis* strains were green-positive.

Both (2/2) *C. tropicalis* were yellow-positive.

All (6/6) *C. glabrata*, (1/1) *Issatchenkia orientalis* (teleomorph of *C. krusei*) and (3/3) *C. krusei* strains were red-positive.

*Candida nivariensis*, *Candida bracarensis*, and *Kluyveromyces delphensis* cross-reacted and produce a red signal. *Candida orthopsilosis* (3/3) and *Candida metapsilosis* cross-reacted to create a green signal. One of two strains of *Candida sojae* cross-reacted and produce a yellow signal. All other (27/27) fungal and (13/13) bacteria strains were negative.

## f. Assay cut-off:

Not applicable

## 2. Comparison studies:

### a. Method comparison of device to conventional methods, as the reference method:

The new modified assay procedure was compared to the original assay procedure and the conventional culture methods.

### b. Matrix comparison:

Not applicable

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3. Clinical studies:

The new procedure was compared to the conventional culture method, and the original procedure. A total of 158 positive blood bottles (114 prospective + 41 seeded with clinical isolates) were tested at three sites. The seeded isolates included 20 C. tropicalis, five C. glabrata, six C. krusei, eight C. lusitaniae, one C. utilis and one C. guilliermondii) at a concentration of 2.5 x 10⁴ CFU/mL. The studies included two commercially available, continuously monitoring blood culture systems (i.e. BacT/ALERT and BACTEC).

Performance Data for Yeast Traffic Light PNA FISH (New) vs. Routine Identification Methods on Yeast-positive Blood Culture Bottles

| Study | Sensitivity
C. albicans/
C. parapsilosis | Sensitivity
C. tropicalis | Sensitivity
C. glabrata/
C. krusei | Specificity | Blood Culture System |
| --- | --- | --- | --- | --- | --- |
| A | 100% (20/20)^{1} | 100% (1/1) | 100% (4/4)^{1} | 100% (4/4) | BacT/Alert |
| B | 100% (11/11) | 100% (5/5) | 100% (17/17) | 100% (2/2) | BacT/Alert |
| C | 100% (28/28)^{2} | 100% (25/25) | 93.3%
(25/26)^{2,3} | 100% (15/15) | BACTEC |
| Total | 100% (59/59) | 100% (31/31) | 97.9% (46/47) | 100% (21/21) | N= 158 |
| | 95% CI (95.1-100) | 95% CI (90.8-100) | 95% CI (88.7-99.6) | 95% CI (86.7-100) | |

1 Includes 1 mixed culture: C. albicans/C. glabrata
2 Includes 2 mixed cultures: C. krusei/C. parapsilosis
3 One C. glabrata was missed by both Yeast Traffic Light PNA FISH (New) and Yeast Traffic Light (K080719) with the BACTEC PEDS Plus/F bottle

Performance Data for Yeast Traffic Light PNA FISH (New) vs. Yeast Traffic Light PNA FISH (K080719) on Yeast-positive Blood Culture Bottles (Clinical and Seeded with Clinical Isolates)

| Study | Positive Agreement
C. albicans/
C. parapsilosis | Positive Agreement
C. tropicalis | Positive Agreement
C. glabrata/ C. krusei | Negative Agreement | Blood Culture System |
| --- | --- | --- | --- | --- | --- |
| A | 100% (20/20)^{1} | 100% (1/1) | 100% (4/4)^{1} | 100% (4/4) | BacT/Alert |
| B | 100% (11/11) | 100% (5/5) | 100% (17/17) | 100% (2/2) | BacT/Alert |
| C | 100% (28/28)^{2} | 100% (25/25) | 100% (25/25)^{2} | 100% (16/16) | BACTEC |
| Total | 100% (59/59) | 100% CI (31/31) | 100% (46/46) | 100% (22/22) | N= 158 |
| | 95% CI (95.1-100) | 95% CI (90.8-100) | 95% CI (93.7-100) | 95% (87.3-100) | |

1 Includes 1 mixed culture: C. albicans/C. glabrata
2 Includes 2 mixed cultures: C. krusei/C. parapsilosis

a. Clinical Sensitivity:
See sensitivity chart above

b. Clinical specificity:
See specificity chart above

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

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Not applicable

4. Clinical cut-off:
Not applicable

5. Expected values/Reference range:
C. albicans and C. parapsilosis cells: multiple bright green fluorescent cells in multiple fields
C. glabrata and C. krusei cells: multiple bright red fluorescent cells in multiple fields
C. tropicalis cells: multiple bright yellow fluorescent cells in multiple fields

The expected C. albicans + C. parapsilosis, C. tropicalis, and C. glabrata + C. krusei positive result rate from yeast positive blood culture bottles is approximately 50%, 9%, and 31%, respectively, based on AdvanDx clinical studies, but may vary depending on institution and patient population.

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

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