Search Results

The B. anthracis Real-Time PCR Assay is an in vitro diagnostic test for the qualitative detection of plasmid and chromosomal DNA sequences from B. anthracis. The assay can be used to test human respiratory samples, whole blood, serum, plasma, swabs from lesions, cerebrospinal fluid, and bacterial culture isolates from individuals suspected of having anthrax. Results generated from direct specimentesting are presumptive for the identification of B. anthracis. Results generated from culture isolate testing should be used in conventional methods for identification of Bacillus anthracis isolates as part of the LRN Bacillus anthracis Testing Algorithm. The diagnosis of anthrax infection must be made based on history, signs, symptoms, exposure likelihood, and other laboratory evidences, in addition to the identification of B. anthracis from cultures or detection directly in clinical specimens. Use is limited to Laboratory Response Network (LRN) designated laboratories. The B. anthracis Real-time PCR Assay is also intended for environmental specimen testing for biothreat detection and response. FDA has not evaluated claims related to the use of this assay on environmental specimens.

The B. anthracis Real-time PCR Assay uses a fluorogenic probe, consisting of an oligonucleotide with a reporter dve (FAM) attached to the 5' end and a quencher dye (BHQ1) attached at or near the 3′ end. The probe anneals to a specific target sequence located between the forward and reverse primers. During the extension phase of the PCR cycle, the 5′ nuclease activity of Taq polymerase degrades the probe causing the reporter dye to separate from the quencher dye and a fluorescent signal is generated. With each cycle, additional reporter dye molecules are cleaved from their respective probes and the fluorescence intensity is monitored during the PCR. The Tag polymerase used in this assay is inactive at room temperature. It must be activated by incubation at 95°C, which also minimizes the production of nonspecific amplification products. Each extracted DNA sample is tested with three B. anthracis primer and probe sets run as individual reactions. The primer and probe sets target genes encoding virulence factors as well as conserved regions of DNA from the B. anthracis chromosome. All primer and probe sets must be positive for the overall result of the B. anthracis Real-time PCR Assay to be interpreted as positive. Any result that is positive for some, but not all target regions, is still considered equivocal and follow-up laboratory investigation should be performed per the LRN Bacillus anthracis testing algorithm.

The B. anthracis Real-Time PCR Assay is an in vitro diagnostic test for the qualitative detection of plasmid and chromosomal DNA sequences from B. anthracis. The assay can be used to test human respiratory samples, whole blood, serum, plasma, swabs from lesions, CSF, pleural fluid, and bacterial culture isolates from individuals suspected of having anthrax. Results generated from direct specimen testing are presumptive for the identification of B. anthracis. Results generated from culture isolate testing should be used in conjunction with other conventional methods for identification of Bacillus anthracis isolates as part of the LRN Bacillus anthracis Testing Algorithm. The diagnosis of anthrax infection must be made based on history, signs, symptoms, exposure likelihood, and other laboratory evidences in addition to the identification of B. anthracis from cultures or detection directly in clinical specimens. Use is limited to Laboratory Response Network (LRN) designated laboratories. The B. anthracis Real-time PCR Assay is also intended for environmental specimen testing for biothreat detection and response. FDA has not evaluated claims related to the use of this assay on environmental specimens.

The B. anthracis Real-time PCR Assay uses a fluorogenic probe, consisting of an oligonucleotide with a reporter dye (FAM) attached to the 5' end and a quencher dye (BHQ1) attached at or near the 3' end. The probe anneals to a specific target sequence located between the forward and reverse primers. During the extension phase of the PCR cycle, the 5′ nuclease activity of Tag polymerase degrades the probe causing the reporter dye to separate from the quencher dye and a fluorescent signal is generated. With each cycle, additional reporter dye molecules are cleaved from their respective probes and the fluorescence intensity is monitored during the PCR. The Tag polymerase used in this assay is inactive at room temperature. It must be activated by incubation at 95°C, which also minimizes the production of nonspecific amplification products. Each extracted DNA sample is tested with three B. anthracis primer and probe sets run as individual reactions. The primer and probe sets target genes encoding virulence factors as well as conserved regions of DNA from the B. anthracis chromosome. All three primer and probe sets must be positive for the overall result of the B. anthracis Real-time PCR Assay to be interpreted as positive. Any result that is positive for some, but not all three target regions, is still considered equivocal and follow-up laboratory investigation should be performed per the LRN Bacillus anthracis Testing Algorithm.

The Joint Biological Agent Identification and Diagnostic System (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 the following: - Human whole blood collected in sodium citrate from individuals suspected of having anthrax - Positive blood cultures - 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 IVD system composed of the portable JBAIDS instrument, laptop computer and software, the JBAIDS Anthrax Detection Kit with two different freeze-dried PCR assays for detection of pathogenic Bacillus anthracis DNA. The system has been validated using four different sample preparation kits for isolating DNA from whole blood (IT 1-2-3TM Platinum Path, QFLOWdma, FLOW Sample Purification Kits), positive blood cultures (IT I-2-3TM SWIPE Sample Purification Kit), and plate cultures (IT 1-2-3™ Platinum Path and SWIPE Sample Purification Kits). Use of the JBAIDS DNA Extraction Control Kit is also recommended. Prior to testing, specimens are processed using BioFire Diagnostic's IT 1-2-3 Sample Purification Kits. The resulting purified sample is added to Target 1 Unknown and Target 1 Inhibition Control vials, along with reconstitution buffer. Target 1 Positive Control and Negative Control vials are prepared using reconstitution buffer and water. When B. anthracis DNA is present, a fragment of B. anthracis DNA is amplified. The amplicon is detected by fluorescence using a specific hydrolysis probe. Each probe is labeled on one end with a fluorescent reporter moiety (6-carboxyfluorescein (6-FAM)) and elsewhere with a quencher moiety (carboxy tetramethylrhodamine (TAMRA)). When the probe is intact, the quencher absorbs the light emitted by the reporter moiety. During PCR, the probe hybridizes to the target sequence before the exonuclease activity of Taq polymerase hydrolyzes the probe, separating the fluorophore from the quencher and permitting detection of the fluorescent signal generated by the reporter. The fluorescent signal increases as additional templates are amplified and more probes are hydrolyzed. JBAIDS Software analyzes the fluorescence amplification curves and reports results as positive, negative, uncertain or inhibited. A failure of the Positive or Negative Control will result in the entire run being called invalid. Retesting is required to resolve uncertain, invalid or inhibited results. The Target 2 assay is used as a supplementary test only after a positive result is obtained with the Target 1 assay.