What are the guidelines for diagnosis and management of Tuberculosis (TB) as per India's National Tuberculosis Elimination Programme (NTEP)?

Diagnosis and Management of TB as per India NTEP Guidelines

Diagnostic Approach

Initial Screening Criteria

All persons with cough lasting 2 weeks or more should be evaluated for TB under NTEP guidelines, along with those presenting with unexplained chronic fever and/or weight loss 1. This represents a lower threshold than international standards which use 2-3 weeks, reflecting India's high TB burden 2.

Sputum Collection and Testing

• Collect at least two sputum specimens (preferably three) on different days for microbiological examination, with at least one early morning specimen 2, 1
• Sputum is the most critical sample for pulmonary TB diagnosis in India 1
• Blood tests have no validated role in pulmonary TB diagnosis and should not be used, despite their popularity in the Indian private sector 1

Microbiological Testing Hierarchy

Primary diagnostic tools under NTEP:

1. CBNAAT (Cartridge-Based Nucleic Acid Amplification Test/GeneXpert): This is the preferred initial rapid diagnostic test for detecting M. tuberculosis and rifampicin resistance simultaneously 3, 4

   • Sensitivity superior to microscopy, detecting cases missed by both ZN and Auramine staining 3
   • Can detect paucibacillary cases more effectively 3

2. Sputum Smear Microscopy:

   • Auramine-O (fluorescent) staining is more sensitive and less time-consuming than conventional Ziehl-Neelsen staining 3
   • Remains cornerstone in high-burden settings despite lower sensitivity 1, 3
   • Positive smears indicate high infectiousness 2

3. Mycobacterial Culture: Gold standard for diagnosis, essential for drug susceptibility testing and diagnosing smear-negative TB 2, 1

Universal Drug Susceptibility Testing (UDST)

India implements UDST for all TB patients using the following algorithm 4:

• All patients undergo rapid genotypic DST (CBNAAT) for rifampicin resistance detection
• If rifampicin-sensitive: proceed to First-Line LPA (Line Probe Assay)
• If rifampicin-resistant: proceed to Second-Line LPA
• Critical gap: Implementation shows only 65% complete the full UDST algorithm 4

Radiographic Evaluation

• Chest X-ray is useful but cannot provide conclusive diagnosis alone and must be followed by sputum testing 1
• For sputum-negative presumptive TB patients, upfront chest X-ray (without waiting for 2-week antibiotic trial) significantly increases case detection and reduces loss to follow-up 5
• Classic findings include apical cavitary lesions, infiltrates, lymphadenopathy, and pleural effusions 6

Important Diagnostic Pitfalls to Avoid

• Never use blood-based antibody tests (IgG/IgM) or IGRAs for active pulmonary TB diagnosis - these are banned by the Government of India for TB diagnosis 1
• Do not rely on single negative sputum specimen 6
• Do not exclude TB based on negative AFB smears alone, as false negatives are common 2, 6
• Avoid fluoroquinolones in diagnostic workup as they can cause transient improvement and mask TB 2

Treatment Management

Standard First-Line Treatment Regimen

All new TB patients should receive a 6-month regimen consisting of 2, 7:

Intensive Phase (2 months):

• Isoniazid + Rifampicin + Pyrazinamide + Ethambutol

Continuation Phase (4 months):

• Isoniazid + Rifampicin

• Fixed-dose combinations are highly recommended to improve adherence and simplify treatment 2

Treatment Monitoring

• Clinical follow-up at least monthly, including evaluation for hepatitis symptoms and adverse effects education 7
• Liver function tests every 2-4 weeks during anti-TB treatment 7
• Sputum examination for treatment response monitoring 2

Drug-Resistant TB Management

Critical programmatic gaps exist in DR-TB management 8:

• Only 69% of microbiologically confirmed cases undergo drug sensitivity testing 8
• Establishment of dedicated district DR-TB treatment centers with airborne infection control is needed 8
• Psychological assessment and counseling should be provided to all DR-TB patients (currently only 30% receive this) 8

Adherence and Patient-Centered Care

Treatment supervision must be patient-centered, based on mutual respect and the patient's needs, with sex-sensitive and age-specific support 2. The provider assumes public health responsibility to ensure adherence until treatment completion 2.

Isolation and Infectiousness Criteria

Patients should remain in isolation until 2:

• Three consecutive negative sputum smears collected on different days, AND
• Clinical improvement demonstrated (reduction in cough, resolution of fever, decreasing bacilli on smear)

Patients are considered infectious if they have positive AFB smears, are coughing, undergoing cough-inducing procedures, and are either not on chemotherapy, just started treatment, or showing poor response 2.

Special Populations

• HIV-infected patients: Require expedited diagnostic evaluation and should receive the same first-line regimen 2
• Children: Diagnosis based on chest radiography consistent with TB plus either exposure history or positive tuberculin skin test 2
• Extrapulmonary TB: Obtain appropriate specimens from suspected sites for microscopy, culture, and histopathology 2

Private Sector Engagement

Over 50% of TB patients in India seek care in the private sector 1, making engagement of all care providers essential for TB control. All practitioners must provide care in conformance with NTEP standards 2.