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AFB Rapid culture by MGIT - BAL / Other Respiratory samples
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No Fasting Required
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Liquid culture (MGIT) for TB in bronchoalveolar lavage or respiratory samples.
₹1,169₹1,670
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AFB Rapid culture by MGIT - BAL / Other Respiratory samples
- Why is it done?
- Purpose: Detects and identifies Mycobacterium tuberculosis (MTB) from bronchoalveolar lavage (BAL) and other respiratory specimens using Mycobacterial Growth Indicator Tube (MGIT) rapid culture methodology
- Primary Indications: Suspected pulmonary or lower respiratory tract tuberculosis, particularly in patients with non-diagnostic sputum samples or those requiring bronchoscopic sampling
- Clinical Circumstances: Immunocompromised patients, radiographic findings suggestive of TB, respiratory symptoms persisting despite negative sputum smears, fever of unknown origin, atypical respiratory presentations, and confirmation of presumptive TB diagnosis
- Advantages: MGIT provides rapid detection (typically 1-2 weeks versus 2-6 weeks with conventional culture), higher sensitivity, automated detection system, and enables drug susceptibility testing
- Normal Range
- Negative Result: No growth of Mycobacterium tuberculosis detected after completion of culture (typically after 42 days or earlier if negative)
- Normal Interpretation: Absence of MTB indicates no active tuberculosis culture growth in the respiratory specimen
- Reference Unit: Qualitative result (Positive/Negative) or quantitative if reported with colony forming units (CFU/mL)
- Detection Time Frame: MGIT typically provides results within 7-14 days for positive cultures; negative results are reported after 42 days of incubation
- Interpretation
- Positive Result - Mycobacterium tuberculosis Isolated: Confirms diagnosis of active tuberculosis; requires immediate notification to public health authorities, initiation of anti-TB therapy, and investigation of contacts; drug susceptibility testing should be performed
- Negative Result: MTB not detected; does not definitively rule out tuberculosis as a single negative culture does not exclude TB, especially in immunocompromised patients; repeat sampling may be considered
- Contaminated Specimen: Growth of non-tuberculous organisms; specimen should be recollected with proper sterile technique
- Factors Affecting Results: Specimen quality and adequacy, timing of collection relative to onset of therapy, patient immune status, prior TB treatment, specimen handling and transportation, contamination during collection or processing
- Clinical Correlation Required: Results must be interpreted in conjunction with clinical presentation, radiographic findings, AFB smear microscopy results, and other diagnostic modalities (PCR, interferon-gamma release assays)
- Associated Organs
- Primary Organs Involved: Lower respiratory tract (lungs, bronchi, bronchioles, alveoli), upper airway structures
- Diseases Diagnosed/Monitored: Active pulmonary tuberculosis, endobronchial TB, bronchial stenosis from TB, TB-associated cavitary disease, miliary tuberculosis
- Associated Conditions: HIV/AIDS with opportunistic infections, bronchial strictures, bronchiectasis, hemoptysis, pleurisy, tuberculoma formation, laryngeal TB
- Potential Complications: Progressive lung tissue destruction, respiratory failure, spontaneous pneumothorax, massive hemoptysis, drug-resistant TB, disseminated/miliary TB, TB meningitis if untreated
- Secondary Organ Involvement: Central nervous system (TB meningitis), lymph nodes (mediastinal lymphadenitis), pleura (tuberculous pleurisy), extrapulmonary dissemination with multi-organ involvement
- Follow-up Tests
- Drug Susceptibility Testing (DST): Mandatory for all positive cultures to guide appropriate antimicrobial therapy and detect MDR-TB or XDR-TB
- AFB Smear Microscopy: Performed on respiratory specimens for initial screening; positive smears indicate higher bacterial load
- Nucleic Acid Amplification Tests (NAAT): GeneXpert MTB/RIF, PCR for rapid MTB detection and rifampicin resistance in 2-4 hours; can be performed simultaneously with culture
- Repeat BAL or Respiratory Sampling: If initial culture is negative but clinical suspicion remains high; improves diagnostic yield
- Clinical Monitoring Tests: Chest X-ray (baseline and follow-up), CT chest, sputum conversion monitoring (AFB smear at 2, 4, and 6 weeks of therapy), microbiological proof of cure
- Immunological Tests: Tuberculin skin test (TST), interferon-gamma release assays (IGRA), CD4+ count in HIV-positive patients
- Contact Tracing: Screening of close contacts with clinical examination and diagnostic testing
- Monitoring Frequency: Monthly AFB smears during intensive phase of therapy (2 months), then every 2-3 months; culture at end of therapy to confirm microbiological cure
- Fasting Required?
- Fasting Status: No - Fasting is NOT required for BAL specimen collection or other respiratory samples
- Pre-procedure Preparation: For bronchoscopy with BAL: NPO (nothing by mouth) for 4-6 hours prior to procedure; patient should notify physician of current medications
- Medication Considerations: Continue routine medications unless otherwise instructed; anticoagulants may need adjustment prior to bronchoscopy; bronchodilators may be administered before procedure
- For Sputum/Expectorated Samples: No special preparation needed; patient should rinse mouth with water before collection to reduce contamination from saliva; early morning sample (first sputum after waking) preferred for higher yield
- General Instructions: Specimens must be collected in sterile containers; proper labeling and transport to laboratory within 2-4 hours; avoid contamination with saliva or external materials; specimens should be maintained at room temperature
How our test process works!
