(119 days)
The Gamma Phage assay is a lytic phage assay specific for Bacillus anthracis. The Gamma Phage assay (common name) can be used on suspect non-hemolytic, aerobic, gram-positive, "ground-glass"- appearing colonies from sheep blood agar in conjunction with other markers and testing for the identification of Bacillus anthracis. The assay is not intended for screening of blood or plasma donors.
Use of this assay is limited to designated laboratory Response Network (LRN) and Department of Defense (D0D).
The gamma phage is a lytic bacteriophage which binds to specific cell-surface components of susceptible bacteria. Their DNA is injected into the bacterium. The gamma phage replicate within the bacterium and produce PlyG lysine (2), resulting in lysis of the infected cell and release of phage. The release of newly synthesized phage leads to another round of phage infection and lysis.
Materials Supplied:
- Bacillus anthracis Gamma Phage Suspension, 0.5 ml
- . Positive Control, Bacillus anthracis Pasteur Strain Spore Suspension, 1.0 ml
- Negative Control, Bacillus cereus Spore Suspension, 1.0 ml ●
Materials required but not supplied:
- . 5% Sheep Blood Agar plate
- . Inoculating loops, 1ul and 10 ul
- Aerosol resistant pipette tips
- . Disinfectant
Equipment required:
- Pipettor, 5-50 µ1
- Incubator, 35+/- 2 °C
- Biological Safety Cabinet, Class II
- Refrigerator, 2-8 ℃ .
Here's a summary of the acceptance criteria and study information for the Gamma Phage Lysis Assay for the Identification of Bacillus anthracis, based on the provided document:
The document describes a Special 510(k) submission (K143592) for the Gamma Phage Lysis assay, which is specific for Bacillus anthracis. The submission states that the only modification made to the previously cleared predicate device (K051794) is a change in the positive control strain from Bacillus anthracis Pasteur strain to Bacillus anthracis Sterne strain. The document claims this change does not impact assay performance.
1. Table of Acceptance Criteria and Reported Device Performance
The document does not explicitly state quantitative acceptance criteria (e.g., specific sensitivity/specificity thresholds) or provide detailed performance metrics (like sensitivity, specificity, accuracy) for the K143592 device itself. Instead, it relies on the substantial equivalence argument, asserting that the performance characteristics are identical to the predicate device because the only change (positive control strain) does not impact assay performance.
Therefore, the "acceptance criteria" can be inferred as maintaining the performance of the predicate device for identifying Bacillus anthracis.
| Metric/Characteristic | Acceptance Criteria (Inferred from Predicate) | Reported Device Performance (K143592) |
|---|---|---|
| Ability to identify Bacillus anthracis | Equivalent to predicate device K051794 | Claimed to be equivalent to predicate device K051794 |
| Specificity for Bacillus anthracis (lytic phage activity) | Equivalent to predicate device K051794 | Claimed to be equivalent to predicate device K051794 |
| Consistency of positive and negative controls | Positive control (Sterne strain) yields expected positive result, Negative control (B. cereus) yields expected negative result. | The document implies this would be met through the use of the specified controls. |
2. Sample Size Used for the Test Set and Data Provenance
The document does not describe a new clinical or laboratory study with a "test set" to establish the performance of the K143592 device independently. The basis for substantial equivalence is that the only change (positive control strain) does not alter the fundamental performance of the assay. Therefore, there is no specific test set sample size or provenance information for K143592 provided in this document as it pertains to proving the performance of the assay itself. The performance relies on the previous clearance of K051794 and the argument that the modification is minor.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts
Not applicable, as no new independent test set study is described for K143592 to establish ground truth for performance. The performance is considered equivalent to the predicate.
4. Adjudication Method for the Test Set
Not applicable, as no new independent test set study is described.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done, and the Effect Size of How Much Human Readers Improve with AI vs. Without AI Assistance
Not applicable. This device is a rapid diagnostic assay for bacterial identification, not an AI-assisted diagnostic tool or an imaging device requiring human reader interpretation in the context of an MRMC study.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done
The device is a laboratory assay. Its performance is inherent to the reagents and protocol. The document does not provide details of an internal "standalone" study for K143592, as its performance is considered unchanged from the predicate device. The assay itself operates "standalone" in the sense that it provides a direct result without human "interpretation" of complex data (like images), but rather observation of lysis.
7. The Type of Ground Truth Used
For the predicate device (K051794) and by extension for K143592, the ground truth for Bacillus anthracis identification would typically be established through:
- Culture and biochemical identification: Standard microbiological methods to identify bacterial species.
- Molecular methods: Such as PCR, targeting specific B. anthracis genes.
- Referral laboratory confirmation: Confirmation by a qualified reference laboratory using a suite of confirmatory tests.
The document implicitly relies on these established methods for identifying Bacillus anthracis to validate the specificity and lytic activity of the gamma phage. The positive and negative controls provided with the kit (e.g., Bacillus anthracis Sterne strain and Bacillus cereus spore suspension) serve as internal ground truth checks for each run of the assay.
8. The Sample Size for the Training Set
Not applicable. This is a traditional diagnostic assay, not a machine learning or AI model that requires a "training set."
9. How the Ground Truth for the Training Set Was Established
Not applicable, as there is no training set for this type of device.
§ 866.3045 In vitro diagnostic device for
Bacillus spp. detection.(a)
Identification. An in vitro diagnostic device forBacillus species (spp.) detection is a prescription device used to detect and differentiate amongBacillus spp. and presumptively identifyB. anthracis and otherBacillus spp. from cultured isolates or clinical specimens as an aid in the diagnosis of anthrax and other diseases caused byBacillus spp. This device may consist ofBacillus spp. antisera conjugated with a fluorescent dye (immunofluorescent reagents) used to presumptively identify bacillus-like organisms in clinical specimens; bacteriophage used for differentiatingB. anthracis from otherBacillus spp. based on susceptibility to lysis by the phage; or antigens used to identify antibodies toB. anthracis (anti-toxin and anti-capsular) in serum. Bacillus infections include anthrax (cutaneous, inhalational, or gastrointestinal) caused byB. anthracis, and gastrointestinal disease and non-gastrointestinal infections caused byB. cereus. (b)
Classification. Class II (special controls). The special controls are set forth in FDA's special controls guideline document entitled “In Vitro Diagnostic Devices forBacillus spp. Detection; Class II Special Controls Guideline for Industry and Food and Drug Administration Staff.” For availability of the guideline document, see § 866.1(e).(c)
Restriction on Distribution. The distribution of these devices is limited to laboratories that follow public health guidelines that address appropriate biosafety conditions, interpretation of test results, and coordination of findings with public health authorities.(d)
Restriction on Use. The use of this device is restricted to prescription use and must comply with the following:(1) The device must be in the possession of:
(i)(A) A person, or his agents or employees, regularly and lawfully engaged in the manufacture, transportation, storage, or wholesale or retail distribution of such device; or
(B) A practitioner, such as a physician, licensed by law to use or order the use of such device; and
(ii) The device must be sold only to or on the prescription or other order of such practitioner for use in the course of his professional practice.
(2) The label of the device shall bear the statement “Caution: Federal law restricts this device to sale by or on the order of a ____”, the blank to be filled with the word “physician” or with the descriptive designation of any other practitioner licensed by the law of the State in which he practices to use or order the use of the device.
(3) Any labeling, as defined in section 201(m) of the Federal Food, Drug, and Cosmetic Act, whether or not it is on or within a package from which the device is to be dispensed, distributed by, or on behalf of the manufacturer, packer, or distributor of the device, that furnishes or purports to furnish information for use of the device contains adequate information for such use, including indications, effects, routes, methods, and frequency and duration of administration and any relevant hazards, contraindications, side effects, and precautions, under which practitioners licensed by law to employ the device can use the device safely and for the purposes for which it is intended, including all purposes for which it is advertised or represented. This information will not be required on so-called reminder-piece labeling which calls attention to the name of the device but does not include indications or other use information.
(4) All labeling, except labels and cartons, bearing information for use of the device also bears the date of the issuance or the date of the latest revision of such labeling.