Understanding the Genexpert Ultra MTB/RIF Test
Alternative Names:
TB DNA Detection by Realtime PCR
Reflex to Rifampicin Resistance by Ultra CBNAAT
CBNAAT Test
CB-NAAT
What It Is: The Genexpert Ultra MTB/RIF test is a molecular diagnostic test used to detect Mycobacterium tuberculosis (MTB) and its resistance to rifampicin (RIF), a key first-line anti-TB drug. This test is particularly useful for rapid diagnosis and detection of drug-resistant tuberculosis (TB).
Why It's Done:
Rapid Diagnosis: The primary purpose of the Genexpert Ultra MTB/RIF test is to provide a quick diagnosis of TB, especially in patients with symptoms suggestive of the disease.
Detecting Drug Resistance: It helps identify TB strains that are resistant to rifampicin, which is crucial for guiding appropriate treatment.
Sample Types:
Sputum: Most commonly used sample for TB testing.
Blood: To detect TB bacteria in the bloodstream.
Urine: To identify TB bacteria in the urinary tract.
Fluid: To test for TB in other bodily fluids, such as cerebrospinal fluid or pleural fluid.
Pus: To identify TB bacteria in pus from abscesses or wounds.
How the Test Works:
Sample Collection: A sample, such as sputum, blood, urine, fluid, or pus, is collected from the patient.
Preparation: The sample is processed to extract DNA from the TB bacteria.
Amplification and Detection: The extracted DNA is amplified using polymerase chain reaction (PCR) technology. The test detects the presence of MTB DNA and mutations associated with rifampicin resistance.
Results: The test provides results in less than two hours, indicating whether MTB and rifampicin resistance are present.
Understanding the Results:
MTB Positive: Indicates the presence of Mycobacterium tuberculosis.
RIF Resistance Detected: Indicates that the TB bacteria are resistant to rifampicin.
MTB Negative: Indicates the absence of Mycobacterium tuberculosis.
Why Your Doctor Might Order This Test:
Symptoms of TB: If you have symptoms such as a persistent cough, fever, night sweats, weight loss, or blood in your sputum, this test can help diagnose TB.
Exposure to TB: If you have been in close contact with someone who has TB, this test can help determine if you have been infected.
Monitoring Treatment: For patients undergoing TB treatment, this test helps monitor the effectiveness of the treatment and detect drug resistance.
Symptoms That Might Prompt This Test:
Persistent cough lasting more than three weeks
Chest pain
Coughing up blood or sputum
Unexplained weight loss
Fatigue and weakness
Night sweats
Lifestyle and Management: Depending on your results, your healthcare provider might recommend further tests, treatments, or lifestyle changes to manage TB effectively. Regular monitoring and follow-up are essential for successful treatment.