C. ALBICANS PNA FISH

K092655 · Advandx, Inc. · NZS · Jan 19, 2010 · Microbiology

Device Facts

• Record ID: K092655
• Device Name: C. ALBICANS PNA FISH
• Applicant: Advandx, Inc.
• Product Code: NZS · Microbiology
• Decision Date: Jan 19, 2010
• Decision: SESE
• Submission Type: Traditional
• Regulation: 21 CFR 866.2660
• Device Class: Class 1

Indications for Use

C. albicans PNA FISH™ is a qualitative nucleic acid hybridization assay intended for identification of Candida albicans on smears made from yeast positive blood cultures containing yeast observed on Gram stain or other microbiological stains. Subculturing of positive blood cultures is necessary for susceptibility testing and/or differentiation of mixed growth.

Device Story

C. albicans PNA FISH is a qualitative nucleic acid hybridization assay used in clinical laboratories. It utilizes Peptide Nucleic Acid (PNA) probes to target specific ribosomal RNA sequences within yeast cells. The device processes smears prepared from yeast-positive blood cultures. The PNA probes are fluorescently labeled; upon hybridization with target C. albicans RNA, the presence of the organism is visualized via fluorescence microscopy. The output is a qualitative identification of C. albicans, which assists clinicians in the rapid diagnosis of fungemia. This rapid identification allows for earlier targeted antifungal therapy compared to traditional culture-based methods, which require subculturing for definitive identification. The device is intended for professional use by laboratory personnel.

Clinical Evidence

No clinical data provided in the document; the submission relies on the performance characteristics of the PNA FISH assay for qualitative identification of C. albicans.

Technological Characteristics

Fluorescence qualitative nucleic acid hybridization assay using PNA probes. The technology relies on the binding of fluorescently labeled PNA probes to specific rRNA sequences in yeast cells, followed by visualization using fluorescence microscopy. The device is a standalone diagnostic kit.

Indications for Use

Indicated for use as an aid in the diagnosis of C. albicans fungemia in patients with yeast-positive blood cultures.

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

A. 510(k) Number:
K092655

B. Purpose for Submission:
SE determination for a modification of the assay procedure for C. albicans 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:
C. albicans specific 26S ribosomal RNA

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

E. Applicant:
AdvanDx, Inc.

F. Proprietary and Established Names:
C. albicans PNA FISH™ Candida albicans Culture Identification Kit

G. Regulatory Information:
| Product Code | Classification | Regulation Section | Panel |
| --- | --- | --- | --- |
| NZA | Class 1 | 21 CFR 866.2660 | 83 Microbiology |

H. Intended Use:

1. Intended use:
C. albicans PNA FISH™ is a qualitative nucleic acid hybridization assay intended for identification of Candida albicans on smears made from yeast positive blood cultures containing yeast observed on Gram stain or other microbiological stains. Subculturing

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of positive blood cultures is necessary for susceptibility testing and/or differentiation of mixed growth.

2. Indication for use:

C. albicans PNA FISH™ is a qualitative nucleic acid hybridization assay, intended for the identification of Candida albicans on smears made from yeast positive blood cultures containing yeast observed on Gram stain or other microbiological stains. Subculturing of positive blood cultures is necessary for susceptibility testing and/or differentiation of mixed growth.

3. Special conditions for use statement:

Prescription use only.

4. Special instrument requirements:

AdvanDx Teflon-coated Microscope Slides. (Cat. AC001) A fluorescent microscope equipped with an AdvanDx Dual Band Filter (Cat. No. AC003)

I. Device Description:

The C. albicans PNA FISH™ Culture Identification Kit contains a 3 mL bottle of fixation solution, a 1.5 mL bottle of fluorescein-labeled PNA probe in hybridization solution, a 50 mL bottle of concentrated wash solution, which must be diluted prior to use, and a 3 mL bottle of mounting medium. The one-well, Teflon-coated microscope slides, glass cover slips and the external quality control organism slides are sold separately. User prepared quality control organism slides are acceptable. After processing, the slides must be examined within two hours by using a fluorescent microscope equipped with a dual band filter.

J. Substantial Equivalence Information:

1. Predicate device name:

C. albicans PNA FISH™

2. Predicate K number

K062461

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3. Comparison with predicate:

| | Similarities | |
| --- | --- | --- |
| Technology | Fluorescence In Situ Hybridization (FISH) using protein nucleic acid (PNA) probe | Same |
| Sample | Positive blood culture | Same |
| PNA Probes | Fluorescein-labeled C.albican specific PNA probe | Same |
| Differences | | |
| --- | --- | --- |
| Item | Device | Predicate |
| Fixed smear treatment | None | Ethanol for 10 minutes and air dried |
| Hybridization at 55°C | 30 minutes | 90 minutes |

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

Not applicable

L. Test Principle:

One drop of fluorescein-labeled, C. albicans-specific PNA probe is added to a methanol, heat, or flame fixed smear, prepared from a positive blood culture bottle. Hybridization is performed during a 30 +/- 5 minute incubation at 55 +/- 1°C, in an incubator or on a slide warmer. The slide is examined by fluorescent microscopy within two hours of staining. C. albicans is identified as multiple bright green fluorescent yeast cells in multiple fields on a reddish background, whereas non-C. albicans cells will not fluoresce.

M. Performance Characteristics (if/when applicable):

1. Analytical performance:

a. Precision/Reproducibility:

A reproducibility study for C. albicans PNA FISH™ assay was performed by using ten reference yeast isolates in different concentrations, once per day with positive and negative controls, over a period of three days at three different sites, by at least two different operators at each site. Results showed 100% precision and reproducibility between and within sites.

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Summary of Reproducibility Results by Sites Across 3 Days

| | Site 1 | Site 2 | Sites 3 | Total Agreement |
| --- | --- | --- | --- | --- |
| Positive Agreement | 54/54 | 54/54 | 54/54 | 100 % (162/162) |
| Negative Agreement | 63/63 | 63/63 | 63/63 | 100% (189/189) |
| Total Agreement | 100% (117/117) | 100% (117/117) | 100% (117/117) | 100% (351/351) |
| Positive/Negative Control | 9/9 | 9/9 | 9/9 | 27/27 |

b. Linearity/assay reportable range:

Not applicable

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

Positive and negative control slides were performed at each testing site. All results were as expected.

d. Detection limit:

The claimed detection limit for C. albicans in blood cultures was determined to be approximately $1 \times 10^{5}$ colony forming units (CFU) per mL by serial dilutions of a C. albicans positive culture. This is consistent with the analytical sensitivity of slide-based staining techniques and is not limited by the test itself, but rather by the general requirement for $1 \times 10^{5}$ CFU/mL for interpretation by standard light microscopy.

e. Analytical specificity:

Specificity of C. albicans PNA FISH probe was evaluated using cultures of 53 laboratory and reference strains (47 fungal strains and 6 strains of other species), the analytical specificity for C. albicans strains positive by PNA FISH™ was $100\%$ (18/18), and $100\%$ (35/35) of the other strains were negative.

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An Advanced BLAST search of the GeneBank nr-database (www.nim.nih~gov/blast) showed that the target sequence is unique for C. albicans, and is not found in other species. The C. albicans PNA probe targets a ribosomal sequence, which is well-suited for the design of species-specific probes. Some C.albicans sequences have a single mismatch to the probe, but no C. albicans sequences have more than one mismatch.

The C. albicans PNA probe sequence is highly specific for identification of C. albicans.

f. Assay cut-off:

Not applicable

2. Comparison studies:

a. Method comparison with predicate device:

The performance of C. albicans PNA FISH™ was evaluated using two different automated blood culture media systems at multiple sites. The data demonstrates that the C albicans PNA FISH™ is comparable with two of the three major blood culture systems, and results from testing are comparable to results obtained by conventional methods. The results are displayed in the table below.

Performance Data for C. albicans PNA FISH (New) vs. C.albicans PNA FISH (K062461) on Yeast-positive Blood Culture Bottles (Clinical and Seeded Samples)

| Study | Positive Agreement C.albicans | Negative Agreement | Blood Culture System |
| --- | --- | --- | --- |
| A | 20/20 | 34/34 | BactT/Alert |
| B | 9/9 | 51/51 | BactT/Alert |
| C | 12/12 | 39/39 | BACTEC |
| Total | 100%(41/41)
95%CI (93.0-100) | 100% (124/124)
95% CI (97.6-100) | N = 165 |

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Performance Data for C. albicans PNA FISH (New) vs. C.albicans PNA FISH (New) vs. Routine Identification Methods on Yeast-positive Blood Culture Bottles (Clinical Samples)

| Study | Sensitivity
C. albicans | Specificity | Blood Culture System |
| --- | --- | --- | --- |
| A | 15/15 | 14/14 | BactT/Alert |
| B | 4/4 | 31/31 | BactT/Alert |
| C | 12/12 | 39/39 | BACTEC |
| Total | 100% (31/31)
95% CI (90.8-100) | 100% (84/84)
95% CI (96.5-100) | N = 115 |

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. Qualitative visual color change.

5. Expected values/Reference range:

The expected C. albicans positive result rate from yeast positive blood culture bottles is 25% - 50%, depending on institutional and patient population

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.