(21 days)
The JBAIDS Anthrax Detection System is a real-time polymerase chain reaction (PCR) test system intended for the qualitative in vitro diagnostic (IVD) detection of target DNA sequences on the pXO1 plasmid (Target 1) and the pXO2 plasmid (Target 2) from Bacillus anthracis. The system can be used to test human whole blood collected in sodium citrate from individuals suspected of having anthrax, positive blood cultures, and cultured organisms grown on blood agar plates. The JBAIDS Anthrax Target 2 assay is used as a supplementary test only after a positive result with the Target 1 Assay.
The JBAIDS Anthrax Target 1 and Target 2 Assays are run on the JBAIDS instrument using the Diagnostic Wizard.
Results are for the presumptive identification of B. anthracis, in conjunction with culture and other laboratory tests. The following considerations also apply:
- The diagnosis of anthrax infection must be made based on history, signs, symptoms, exposure likelihood, and other laboratory evidence, in addition to the identification of pXO1 and pXO2 targets either from cultures or from direct blood specimens.
- The assays have not been evaluated with blood from individuals without clinical signs or symptoms who were presumed exposed and who subsequently developed anthrax (inhalation or other forms of the disease), or from individuals with any form of anthrax (inhalational, cutaneous, or gastrointestinal).
- The level of plasmid targets that would be present in blood from individuals with early systemic infection is unknown.
- The definitive identification of B. anthracis from colony growth, liquid blood culture growth, or from blood specimens requires additional testing and confirmation procedures in consultation with public health or other authorities for whom reports are required.
The safety and effectiveness of other types of tests or sample types (not identified as "For in vitro diagnostic use") have not been established.
The Joint Biological Agent Identification and Diagnostic System (JBAIDS) Anthrax Detection System is a fully integrated in vitro diagnostic (IVD) system composed of the following:
- JBAIDS instrument with laptop computer
- Software
- Two different freeze-dried reagent assays (in one kit) for the qualitative detection of pathogenic Bacillus anthracis
- Four different sample preparation protocols, two for isolating target DNA from whole blood, one for processing blood culture, and another for processing colonies.
The JBAIDS instrument, using Polymerase Chain Reaction (PCR) technology, is a portable thermocycler and real-time fluorimeter. The JBAIDS Anthrax Detection Kit is specially designed for PCR in glass capillaries using the JBAIDS instrument and hydrolysis probes for sequence-specific detection of B. anthracis DNA found on the pX01 plasmid (Target 1) and the pX02 plasmid (Target 2).
The reagent kit contains four different types of freeze-dried reagent vials: Positive Controls, Negative Controls, Inhibition Controls, and Unknowns (used for testing the patient sample). Each JBAIDS assay requires a Positive and Negative Control, and each sample is tested using both an Inhibition Control vial and an Unknown reagent vial.
Before testing, whole-blood samples are purified using the Idaho Technology IT 1-2-3 FLOW or QFLOWdir Sample Purification Kit (or validated equivalent), while blood culture and direct culture specimens are prepared using the IT 1-2-3 SWIPE Sample Purification Kit (or validated equivalent). The resulting purified sample is added to an Unknown reagent vial and an Inhibition Control reagent vial, along with reconstitution buffer. A Positive Control and a Negative Control vial are prepared using reconstitution buffer and reagent grade water. Aliquots from each reagent vial are transferred to two reaction capillaries that are tested together in the JBAIDS instrument. The instrument is programmed to perform heating and cooling cycles that drive the PCR process. The heating and cooling cycles are generated using a heating coil and varying fan speeds. Fluorescence emission is monitored over one of three wavelengths, and the instrument software interprets the change in fluorescence to determine whether the target DNA is present.
When the organism is present, a fragment of B. anthracis DNA is amplified using specific primers. The amplicon is detected by fluorescence using a specific hydrolysis probe. The hydrolysis probe contains a short oligonucleotide that hybridizes to an internal sequence of the amplified fragment during the annealing phase of the PCR cycle. This probe has the 5' and 3' ends labeled with a reporter dye and a quenching dye, respectively. When the probe hybridizes to the specific DNA target, the Taq polymerase enzyme, replicating the target-specific DNA, hydrolyzes the probe, which separates the two fluorophores, thus allowing the reporter dye to fluoresce.
The level of fluorescence from each unknown sample and control is measured by the JBAIDS instrument. JBAIDS Software analyzes fluorescence amplification curves and reports results as "Positive," "Negative," "Inhibited," or "Uncertain." A failure of the Positive or Negative Control will result in the entire run being called "Invalid." Failure of the Inhibition Control yields an Inhibited result for the associated sample and requires retesting of that sample.
The JBAIDS Anthrax Detection System is a real-time PCR test system intended for the qualitative in vitro diagnostic (IVD) detection of target DNA sequences on the pXO1 plasmid (Target 1) and the pXO2 plasmid (Target 2) from Bacillus anthracis.
1. Acceptance Criteria and Reported Device Performance:
The provided document describes a method comparison and carry-over study rather than specific acceptance criteria thresholds with a pass/fail outcome. The studies aim to demonstrate equivalence between a new sample purification kit (IT 1-2-3 QFLOWdna) and an existing one (IT 1-2-3 FLOW).
| Acceptance Criteria (Implied) | Reported Device Performance |
|---|---|
| Method Comparison (Equivalence in detecting B. anthracis at LOD) | All six samples spiked at LOD were positive with both Target 1 and Target 2 assays using both IT 1-2-3 QFLOWdna and IT 1-2-3 FLOW. Samples purified with QFLOWdna showed equivalent or better recovery and purity of DNA. |
| Method Comparison (Specificity/Negative Sample Performance) | All 16 normal healthy donor samples processed with IT 1-2-3 QFLOWdna protocol gave negative results for both assays. For IT 1-2-3 FLOW, 15 samples were negative for Target 1 (one inhibited), and all 16 were negative for Target 2. The QFLOWdna showed better or equivalent performance in negative samples. |
| Carry-over (Rate of False Positives from Strong Positive Samples) | For QFLOW™ protocol, carry-over observed in 2.4% (1/42) of negative capillaries for Target 1 assay and 0% (0/42) for Target 2. The carry-over rate for IT 1-2-3 FLOW protocol was 0% (0/12) for both Target 1 and Target 2. The rates were determined to be equivalent. |
2. Sample Sizes and Data Provenance:
- Method Comparison - Spiked Samples: 6 citrated whole blood samples spiked with B. anthracis at the Limit of Detection (LOD).
- Method Comparison - Negative Samples: 16 normal healthy donors (citrated whole blood samples).
- Carry-over Study:
- Strongly positive samples (spiked at 5 x 10" CFU/mL) processed next to negative (unspiked) samples.
- QFLOW™ protocol: 42 negative capillaries were assessed for carry-over.
- IT 1-2-3 FLOW protocol: 12 negative capillaries were assessed for carry-over.
- Data Provenance: Not explicitly stated (e.g., country of origin). The studies appear to be prospective as they were specifically performed to evaluate the new sample purification kit.
3. Number of Experts and Qualifications for Ground Truth: No information provided. This is a molecular diagnostic test, and ground truth would typically be established based on the known spiked concentration of B. anthracis or confirmed negative status of healthy donor samples, rather than expert interpretation of images or clinical data.
4. Adjudication Method: Not applicable. For this type of molecular test, objective results (positive/negative/inhibited) are generated by the instrument based on fluorescence curves and software analysis, not human interpretation requiring adjudication.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study: No. This is not an imaging device or one that relies on human interpretation for diagnosis; therefore, an MRMC study comparing human readers with and without AI assistance is not applicable.
6. Standalone Performance: Yes, the device's performance results (detection of B. anthracis DNA, specificity in negative samples, carry-over rate) are reported for the algorithm (JBAIDS Anthrax Detection System) based on its analysis of samples. The system reports "Positive," "Negative," "Inhibited," or "Uncertain" results without human intervention in the interpretation of the raw data.
7. Type of Ground Truth Used:
- For the method comparison using spiked samples: The ground truth was based on the known presence of B. anthracis DNA at a defined concentration (LOD).
- For the method comparison using healthy donor samples: The ground truth was the known absence of B. anthracis DNA in these healthy individuals.
- For the carry-over study: The ground truth for positive samples was their known high concentration of B. anthracis, and for negative samples, it was the known absence of B. anthracis.
8. Sample Size for the Training Set: Not specified. This document describes performance validation for a specific modification (new sample purification kit) rather than the initial development and training of the PCR assay's core algorithms. PCR assays are typically developed based on laboratory experiments to define primer/probe specificity and amplification efficiency, rather than machine learning on a "training set" in the traditional sense.
9. How the Ground Truth for the Training Set Was Established: Not specified. As mentioned above, for a PCR assay, "training" involves optimizing molecular biology parameters, and ground truth is based on known biological characteristics of the target organism and non-target organisms.
§ 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.