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Mycobacterium tuberculosis Complex and Rifampin Resistance, PCR, Sputum
MessageOrder as a miscellaneous test.
Test Code
94577
Alias/See Also
94577
AFB PCR
AFB RIFAMPIN RESIS PCR
AFB PCR
AFB RIFAMPIN RESIS PCR
CPT Codes
87801
Preferred Specimen
5 mL sputum collected in a sterile leak-proof container
Minimum Volume
2 mL
Instructions
Expectorated sputum: Instruct patient to gargle with water and cough deeply.
Transport Temperature
Refrigerated (cold packs)
Specimen Stability
Room temperature: Unacceptable
Refrigerated: 5 days
Frozen: Unacceptable
Refrigerated: 5 days
Frozen: Unacceptable
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Specimen received in formalin and/or alcohol • 24-hour pooled sputum • Samples with obvious food particles or solid particulate • Processed/concentrated sputum specimen from client
Methodology
Real-Time Polymerase Chain Reaction
Setup Schedule
Set up: Mon-Sat; Report available: Next day
Reference Range
MTB Complex | Not detected |
Rifampin Resistance | Not detected |
Clinical Significance
Globally, about 2 billion people are infected with MTB. In 2010, 8.8 million people developed active disease and 1.4 million people lost their lives to the illness. There were 9951 new cases of tuberculosis reported in the United States in 2012 (a rate of 3.2 cases per 100,000). In 2011, 536 deaths were attributed to tuberculosis infections.
Standard treatment regimens for tuberculosis involve prolonged administration of multiple drugs and is usually highly effective. However, MTB-complex strains that are resistant to one or more of first line drugs require individualized treatment. Rifampin resistance is often an indication of multidrug resistance to tuberculosis (MDR TB), which is defined as resistance to at least rifampin (RIF) and isoniazid (INH). In the Unites States overall RIF resistance is approximately 1.8% with approximately 90% of these strains resistant to at least RIF and INH.
Active pulmonary TB is a highly infectious airborne disease. All patients in healthcare facilities with suspected TB should be maintained in respiratory isolation according to recommended infection control guidelines. Patients with HIV infection and pulmonary TB are more likely to have sputum samples that are acid-fast bacilli (AFB) smear negative than patients with pulmonary TB alone. Overall rates of detection of MTB-complex with the Xpert (TM) MTB/RIF Assay may be lower in settings with a high percentage of HIV-infected patients relative to populations where the percentage of patients with HIV infection is lower and AFB smear-positive TB is higher.
Standard treatment regimens for tuberculosis involve prolonged administration of multiple drugs and is usually highly effective. However, MTB-complex strains that are resistant to one or more of first line drugs require individualized treatment. Rifampin resistance is often an indication of multidrug resistance to tuberculosis (MDR TB), which is defined as resistance to at least rifampin (RIF) and isoniazid (INH). In the Unites States overall RIF resistance is approximately 1.8% with approximately 90% of these strains resistant to at least RIF and INH.
Active pulmonary TB is a highly infectious airborne disease. All patients in healthcare facilities with suspected TB should be maintained in respiratory isolation according to recommended infection control guidelines. Patients with HIV infection and pulmonary TB are more likely to have sputum samples that are acid-fast bacilli (AFB) smear negative than patients with pulmonary TB alone. Overall rates of detection of MTB-complex with the Xpert (TM) MTB/RIF Assay may be lower in settings with a high percentage of HIV-infected patients relative to populations where the percentage of patients with HIV infection is lower and AFB smear-positive TB is higher.
Performing Laboratory
Quest Diagnostics Nichols Institute
14225 Newbrook Drive
Chantilly, VA 20153
Last Updated: May 13, 2022