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The Xpert® Hemorrhagic Fever test, performed on the GeneXpert® Edge X system, is an automated multiplex real-time reverse transcription polymerase chain reaction (RT-PCR) test intended for the qualitative in vitro detection and identification of RNA from multiple biothreat agents:
• Ebola virus (including Zaire, Sudan, Taï Forest, and Bundibugyo, not differentiated)
• Crimean-Congo hemorrhagic fever (CCHF) virus
• Marburg virus
• Lassa virus

The Xpert Hemorrhagic Fever test uses EDTA-treated whole blood specimens collected by capillary or venous draw from individuals with signs and symptoms of the suspected infections and/or individuals who are at risk for exposure or may have been exposed to these agents.

The Xpert Hemorrhagic Fever test is indicated as an aid in the diagnosis of viral hemorrhagic fevers and results should be used in conjunction with other clinical, epidemiologic and laboratory data in accordance with the guidelines provided by the Centers for Disease Control and Prevention (CDC) and United States Department of Defense (DoD).

The Xpert Hemorrhagic Fever test results are for the presumptive identification of Ebola, CCHF, Marburg and Lassa viruses. Definitive identification requires additional testing and confirmation procedures in consultation with the appropriate public health authorities for whom reports may be necessary. Positive results do not rule out co-infection with organisms not included in the Xpert Hemorrhagic Fever test. The organism(s) detected may not be the definite cause of symptoms. Negative results do not preclude infection with these agents and should not be used as the sole basis for diagnosis, treatment, or other patient management decisions.

Xpert Hemorrhagic Fever ("Xpert HF") is an automated in vitro diagnostic test for the qualitative detection and identification of RNA from Ebola virus (including Zaire, Sudan, Taï Forest, and Bundibugyo, not differentiated), Crimean-Congo hemorrhagic fever (CCHF) virus, Marburg virus, and Lassa virus in EDTA-treated whole blood specimens collected by capillary or venous draw from individuals with signs and symptoms of the suspected infections and/or individuals who are at risk for exposure or may have been exposed to these agents.

The Xpert HF test is performed on the GeneXpert Edge X system, which consists of an instrument and a mobile tablet with preloaded software for performing the test and viewing the results. The GeneXpert Edge X system automates and integrates sample extraction, nucleic acid purification and amplification, and detection of target sequences from EDTA-treated whole blood specimens by using reverse transcription (conversion of RNA templates into DNA) followed by real-time PCR. The GeneXpert Edge X instrument is equipped with one GeneXpert module which contains a syringe drive for dispensing fluids (i.e., the syringe drive activates the plunger that works in concert with the rotary valve in the cartridge to move fluids between chambers), an ultrasonic horn for lysing cells or spores, and a proprietary I-CORE® thermocycler for performing real-time RT-PCR and PCR as well as detection. The GeneXpert Edge X system requires the use of a single-use disposable GeneXpert cartridge that contains target-specific reagents and carries out the RT-PCR and PCR processes. Because the cartridges are self-contained, the risk of cross-contamination between samples is minimized.

The Xpert HF test includes reagents for the detection of RNA from Ebola virus (including Zaire, Sudan, Taï Forest, and Bundibugyo, not differentiated), Crimean-Congo hemorrhagic fever (CCHF) virus, Marburg virus, and Lassa virus in EDTA-treated capillary or venous whole blood specimens. The primers and probes in the Xpert HF test are designed to amplify and detect unique sequences in the genes that encode the following protein: Ebola nucleoprotein (NP), Lassa glycoprotein precursor (GPC), CCHF polymerase (L), and Marburg nucleoprotein (NP). A Sample Processing Control (SPC), a Sample Adequacy Control (SAC), and a Probe Check Control (PCC) are also included in the cartridge. The SPC is present to control adequate extraction and processing of the target sequences and to monitor for the presence of inhibitors in the PCR reaction. The SAC ensures that sufficient human cells have been added in test cartridge. The PCC verifies reagent rehydration, PCR tube filling in the cartridge, probe integrity, and dye stability.

Venous and capillary whole blood specimens collected into EDTA anticoagulant tubes are added to an off-board sample reagent (SR) vial in which the sample is inactivated. The inactivated sample is then added to the Xpert HF cartridge before being loaded onto the GeneXpert Edge X instrument, which performs hands-off, automated sample processing, and real-time RT-PCR for the detection of these viral RNAs.

The results are interpreted by the Cepheid OS X software from measured fluorescent signals and embedded calculation algorithms and are clearly shown in the "Result Summary Page". The Xpert HF test provides test results for Ebola, CCHF, Marburg and Lassa. If encountered, NO RESULT-REPEAT TEST and INSTRUMENT ERROR test results are also reported and the user is instructed to repeat the test.

The Xpert HF test is designed for use with fingerstick K2-EDTA whole blood (CWB) or EDTA-treated whole blood obtained from venous draw (VWB). The ancillary EDTA anticoagulant whole blood collection tubes verified and/or validated for use with the Xpert HF test included:

• BD Microtainer® Contact-Activated Lancet (P/N 366594 or P/N 366578)
• BD Microtainer® Blood Collection Tubes (P/N 3665974) for capillary whole blood collection
• BD Vacutainer® Blood Collection Tubes for venous whole blood collection
o P/N 367841 (2 mL)
o P/N 366643 (10 mL)
o P/N 367899 (6 mL)

These ancillary collection tubes allow VWB and CWB specimens from patients to be collected, preserved and transported to the laboratory prior to analysis with the Xpert HF test.

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