Great challenges face the global community, including the United States, with the worldwide re-emergence of TB and increased number of multi-drug resistant. GeneXpert for TB diagnosis: planned and purposeful implementation .. for many countries because the software is currently only in English. Diagnosing Pulmonary Tuberculosis with the Xpert MTB/RIF Test . Note: Before starting the test, ensure that the GeneXpert Dx System is.

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GeneXpert MTB/RIF

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If the problem continues, please let us know and we’ll try to help. An unexpected error occurred. Testing is standardized and requires only moderate laboratory infrastructure and training. However, in many areas of the world, TB diagnosis still relies on insensitive, poorly standardized sputum microscopy methods.

Ineffective Tubercu,osis detection and the emergence and transmission of drug-resistant MTB strains increasingly jeopardize global TB control activities. Effective diagnosis of pulmonary TB requires the availability – on a global scale – of standardized, easy-to-use, and robust diagnostic tools that would allow the direct detection of both the MTB complex and resistance to key antibiotics, such as rifampicin RIF. Cepheid’s Sunnyvale, CA, U. It is a nucleic-acids amplification test for 1 the detection of MTB complex DNA in sputum or concentrated sputum sediments; and 2 the detection of RIF resistance-associated mutations of the rpoB gene.

Tubercylosis system consists of an instrument, personal computer, barcode scanner, and preloaded software for running tests and viewing the results. Because the cartridges are self-contained, cross-contamination between samples is eliminated.

Current FIND-negotiated prices, along with the list of countries eligible for the discounts, are available on the web. Standard 2 of the International Standards for Tuberculosis Care states that all patients suspected of having pulmonary TB should submit at least two sputum specimens for bacteriological examination.

When possible, at least one early-morning specimen should be obtained, as sputum collected at this time has the highest yield. Do note that it should not be used for monitoring the effects of drug therapy 7 because bacterial DNA might persist following antimicrobial therapy.


Treat clinical specimens, including used cartridges, as if capable of transmitting infectious agents.

GeneXpert MTB/RIF – Wikipedia

Use proper precautions, such as wearing protective disposable gloves, laboratory coats and eye protection, and follow your institution’s safety procedures and guidelines.

Process only as many specimens at one time, as there are GeneXpert Dx System modules available to run the test! Process only as many specimens at one time as there are GeneXpert Dx System modules available to run the tests! Start the genespert within 30 minutes of adding the sample to the cartridge!

Dispense slowly to minimize the risk of aerosol formation! Five differently colored fluorogenic nucleic acid hybridization probes, called molecular beacons, interrogate the entire bp core. Since molecular beacons fluorescence only when they are bound to their targets, i. The SPC should be positive in a negative sample and can be negative or positive in a positive sample. The test result will be “Invalid” if the SPC is not detected in a tiberculosis test. Before the start of the PCR reaction, the GeneXpert Dx System measures the fluorescence signal from the probes to monitor bead rehydration, reaction-tube filling, probe integrity and dye stability.

The PCC passes if the fluorescence signal from the probes meets the assigned acceptance criteria. The results are interpreted by the GeneXpert Genxpert System from measured fluorescence signals and embedded calculation algorithms and are displayed in the View Results window 9as indicated below:. Presence or absence of MTB cannot be determined: SPC does not meet acceptance criteria, i. Click here to view larger figure.

Invalid test result, i. SPC does not meet acceptance criteria, because the sample was not properly processed, or because PCR was inhibited. As clinically relevant MTB concentrations all fall within the linear range of the assay, the assay provides semi-quantitative estimates of the bacterial load. The limit of detection lies at least two orders of magnitude lower than that of conventional microscopy. Furthermore, the simultaneous detection of RIF-resistant MTB is a significant benefit in the setting of point-of-care testing in the era of drug-resistant TB.

To date only limited published data on the assay’s performance for diagnosing pulmonary TB in clinical settings are available. The overall pre-test probability of culture-confirmed TB in the study population was The sensitivity was The authors acknowledge W. Looney for carefully reviewing the manuscript.


You must be signed in to post a comment. Please sign in or create an account. Skip to content Immunology and Infection. Expectorated Sputum Samples Note: Alternatively, the entire specimen may be processed in the original leak-proof sputum collection container.

Replace the lid, and shake the tube vigorously times. Alternatively, the mixture may be vortexed 30 sec. Allow the tube to stand upright for 5 min at room temperature. Shake the tube vigorously times. Alternatively, use a vortex 30 sec. Allow the tube to stand upright for another 10 min at room temperature. Add at least 0. Open the cartridge lid. Close the cartridge lid.

GeneXpert for TB diagnosis: planned and purposeful implementation

Starting the Test Note: On the Windows desktop, double-click the GeneXpert Dx shortcut icon. Log on to the GeneXpert Dx System software using your user name and password. The Scan Cartridge Barcode dialog box appears. The Create Test window appears. Click Start Testand enter your password in the dialog box that appears.

Open the instrument module door with the blinking green light, and load the cartridge. The test es;aol and the light stops blinking and remains constantly green.

When the test is finished, the tuberculosjs turns off. Wait until the system releases the door lock at the end of the run, then open the module door and remove the cartridge. Dispose of used cartridges in the appropriate waste containers according to your institution’s standard practices.

The results are interpreted by the GeneXpert Dx System from measured fluorescence signals and embedded calculation algorithms and are displayed in the View Results window 9as indicated below: This article is Free Access. The MODS method for diagnosis of tuberculosis and multidrug resistant tuberculosis ….

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