AFB Rapid Culture by MGIT - Sputum

Lung

Report in 1176Hrs

At Home

No Fasting Required

Details

Rapid TB culture using sputum sample.

₹1,169₹1,670

30% OFF

AFB Rapid Culture by MGIT - Sputum: Comprehensive Medical Test Guide

Why is it done?
- Detects Mycobacterium tuberculosis (TB) bacteria in sputum samples using the MGIT (Mycobacteria Growth Indicator Tube) rapid culture system, which provides faster results than traditional culture methods
- Diagnoses active pulmonary tuberculosis in patients presenting with respiratory symptoms such as persistent cough, fever, night sweats, and weight loss
- Confirms TB infection in patients with positive tuberculin skin tests or interferon-gamma release assays
- Monitors treatment response in TB patients to assess bacterial load reduction during therapy
- Identifies drug-resistant TB strains for appropriate treatment planning
- Ordered when patients are suspected of having TB-related pneumonia or other respiratory infections caused by mycobacteria
- Typically performed in immunocompromised patients (HIV/AIDS) presenting with respiratory symptoms
- Used for surveillance and epidemiological monitoring in high-risk populations and healthcare settings
Normal Range
- Normal Result: NEGATIVE or NOT DETECTED Indicates the absence of Mycobacterium tuberculosis growth in the sputum sample within the detection timeframe (typically 2-6 weeks)
- Negative Result Interpretation: Suggests patient does not have active pulmonary tuberculosis or has successfully cleared the infection with treatment
- Units of Measurement: Culture result is reported as presence or absence (qualitative) rather than quantitative values
- Reference Standard: A truly negative result requires proper sample collection, transport, and processing with MGIT system confirmation
- Time to Result: MGIT typically provides negative results within 7-14 days if no growth is detected
- Abnormal Result: POSITIVE or M. tuberculosis DETECTED Indicates growth of Mycobacterium tuberculosis in the MGIT culture system
- Borderline/Contaminated: Samples may be reported as 'contaminated' if non-TB mycobacteria or other organisms overgrow the culture
Interpretation
- POSITIVE Result: Indicates confirmed active tuberculosis infection. The patient has viable M. tuberculosis organisms in the respiratory tract and is likely infectious
- NEGATIVE Result: Suggests absence of active TB in the sample. However, negative results do not completely exclude TB; multiple negative samples may be needed to rule out TB
- Time to Detection: MGIT rapidly detects TB growth, typically reporting positive results within 2-6 weeks (much faster than conventional culture methods requiring 8+ weeks)
- Clinical Significance: Positive result requires immediate reporting for infection control measures and treatment initiation
- Factors Affecting Results: Sample quality (adequate sputum volume), proper collection technique, transportation conditions, and specimen storage can impact culture accuracy
- Pre-analytical Variables: Contamination during collection, improper storage temperature, delayed processing, or use of expired culture media can lead to false negatives or inconclusive results
- Bacterial Load Correlation: Culture positivity correlates with higher bacillary load; patients with low bacillary loads may show positive AFB smear but negative culture
- Species Identification: Positive cultures can be further identified to confirm M. tuberculosis complex versus non-tuberculous mycobacteria (NTM) species
- Drug Susceptibility Testing: Positive MGIT cultures allow for susceptibility testing to determine antibiotic resistance patterns essential for treatment decisions
- Treatment Monitoring: Serial negative cultures after positive baseline indicate successful treatment response and declining infectivity
Associated Organs
- Primary Organ System: Respiratory system (lungs, bronchi, trachea, and other upper airway structures)
- Pulmonary Tuberculosis: Active lung infection causing cavitary or non-cavitary lesions, pneumonia, bronchiectasis, and progressive lung damage
- Secondary Organ Involvement: TB can spread to lymph nodes (hilar lymphadenopathy), pleura (pleurisy), and potentially disseminate to other organs
- Associated Diseases: Pulmonary tuberculosis, endobronchial TB, TB pneumonia, chronic pulmonary cavitation, and bronchial strictures
- Complications of Abnormal Results: Hemoptysis (coughing blood), respiratory failure, spontaneous pneumothorax, empyema, and acute respiratory distress syndrome
- Systemic Complications: Progressive constitutional symptoms including fever, malaise, weight loss, and immunologic compromise
- Transmission Risk: Positive culture results indicate patient is potentially infectious and poses transmissibility risk to susceptible contacts
- Immunological Consequences: Chronic infection leads to adaptive immune response activation and potential immune dysregulation in HIV co-infected patients
- Organ Damage Progression: Untreated TB causes progressive fibrosis, tissue necrosis, and irreversible pulmonary function decline
Follow-up Tests
- Drug Susceptibility Testing (DST): Performed on positive MGIT cultures to determine resistance to first-line (isoniazid, rifampicin) and second-line TB medications
- Mycobacterial Species Identification: MALDI-TOF mass spectrometry or molecular testing to confirm M. tuberculosis complex versus non-tuberculous mycobacteria species
- Acid-Fast Bacilli (AFB) Smear Microscopy: Repeat sputum smears to assess bacterial burden and treatment response (should convert to negative within 2-8 weeks of therapy)
- Chest X-ray: Initial imaging to assess extent of pulmonary involvement and baseline for monitoring treatment response
- TB Molecular Testing (GeneXpert MTB/RIF): Rapid nucleic acid amplification test to detect TB and rifampicin resistance within 2 hours, complementary to culture
- HIV Testing: Essential for TB-positive patients to assess immunologic status and guide antiretroviral therapy and TB treatment decisions
- CD4 Count and Viral Load: In HIV co-infected patients to determine baseline immune function and monitor response to antiretroviral therapy
- Baseline Laboratory Tests: Liver function tests, renal function, and baseline CBC to monitor for drug toxicity during TB treatment
- Repeat Sputum Cultures: Typically after 2-4 weeks of therapy to confirm treatment response; negative cultures indicate successful bacteriologic response
- Contact Investigation: Testing of close contacts to identify secondary TB cases or latent infections requiring preventive therapy
- Monitoring Frequency: Sputum cultures recommended at 2, 4, and end of continuation phase; more frequent monitoring for drug-resistant TB cases
- End-of-Treatment Assessment: Final sputum culture to confirm cure; negative result indicates successful treatment completion
Fasting Required?
- Fasting Requirement: NO - Fasting is not required for sputum collection
- Sample Collection: Sputum is collected through spontaneous coughing without regard to food intake or fasting status
- Medication Considerations: Patients should not discontinue prescribed medications. Continue all medications as directed by healthcare provider
- Pre-Collection Instructions: Rinse mouth with water (not mouthwash) 15-30 minutes before collection to reduce contamination from oral flora
- Optimal Collection Timing: Early morning sputum samples are preferred as they tend to have higher bacterial yield from overnight accumulation
- Sample Volume: Minimum 5-10 mL of deep cough sputum (not saliva) collected in sterile container for adequate culture
- Collection Technique: Patient should take deep breaths and cough forcefully from lower respiratory tract to obtain true sputum rather than saliva
- Sample Transport: Sputum must be transported to laboratory promptly at room temperature; refrigeration is not needed and may reduce viability
- Container Specifications: Use sterile, leak-proof containers with secure lids; containers must be labeled with patient identifiers and collection date/time
- Special Precautions: Patients should be educated on infection control during collection to prevent aerosol transmission; use of tissue/napkin recommended
- Sample Handling: Processed samples should be handled in biosafety level 3 laboratory facilities due to TB transmission risk
- Turnaround Time: MGIT culture results typically reported within 2-6 weeks; negative results may require up to 8 weeks for final confirmation

How our test process works!