Overview: Tuberculosis Final Diagnosis Panel
Introduction: The Tuberculosis Final Diagnosis Panel is a diagnostic tool designed for tuberculosis diagnosis using serum samples. In India, TB remains a major public health challenge (~2.6 million cases/year, highest globally), with extrapulmonary TB common in rural/low-SES populations due to malnutrition and delayed care. High morbidity from under-testing leading to delayed ATT initiation, transmission, or MDR progression. Per TB practices aligned with ICMR, National TB Elimination Programme (NTEP), and Revised National Tuberculosis Control Programme guidelines, the test employs immunoassay/microscopy for QuantiFERON-TB Gold (IGRA), AFB smear, ESR, CRP, ADA, TB-IgG, TB-IgM, and chest X-ray correlation over 1â€"2 days with high accuracy, valuable for confirming active TB (especially extrapulmonary) and monitoring response. This diagnostic falls under infectious disease screening and targets patients with fever, weight loss, lymphadenopathy, or pleural effusion, addressing accurate detection to guide ATT and contact tracing. With elevated morbidity due to underdiagnosis, the test supports public health efforts by enabling comprehensive TB confirmation and reducing mortality/transmission. Its serum-based approach ensures reliable multi-marker assessment.
Other Names: TB Diag Pnl.
FDA Status: FDA approved, CLIA certified for biochemistry/immunology/clinical pathology, compliant with 2025 standards.
Historical Milestone: IGRA + inflammatory markers standard in TB diagnosis; in India, integrated in NTEP.
Purpose: The test assesses 8 parameters including QuantiFERON-TB Gold to guide TB diagnosis, detect immune/inflammatory response, inform ATT.
Test Parameters: 1. QuantiFERON-TB Gold (IGRA), 2. AFB Smear, 3. ESR, 4. CRP, 5. ADA, 6. TB-IgG, 7. TB-IgM, 8. Chest X-ray Correlation.
Pretest Condition: No fasting required; patients should have TB suspicion.
Specimen: 3 mL serum in 1 SST, transported within specified times to maintain sample viability.
Sample Stability at Room Temperature: 8 hours with proper handling to preserve analyte integrity, ensuring reliable test performance.
Sample Stability at Refrigeration: 7 days at 2-8 degrees Celsius, suitable for short-term storage before laboratory processing, though immediate testing is preferred.
Sample Stability at Frozen: 6 months at -20 degrees Celsius, allowing long-term storage for retesting, though freezing may affect some analytes.
Medical History: Patients should provide details on cough, weight loss, contact.
Consent: Written informed consent is required, detailing the test's purpose, potential risks of undetected TB including transmission/death, benefits of screening, and minimal discomfort from venipuncture.
Procedural Considerations: The test involves sample processing using immunoassay/microscopy by trained personnel to ensure sterile technique, avoid hemolysis, and interpret results within 1â€"2 days using provided controls. Laboratories must maintain a controlled environment, adhere to quality assurance protocols.
Factors Affecting Result Accuracy: Delays beyond stability periods, improper storage conditions, hemolysis can affect results. Correlation with clinical evaluation or additional testing is recommended to confirm findings.
Clinical Significance: Positive IGRA + elevated ADA/CRP/ESR supports TB diagnosis, necessitating specialist input.
Specialist Consultation: Pulmonologists or infectious disease specialists should be consulted for management.
Additional Supporting Tests: GeneXpert, culture for confirmation.
Test Limitations: IGRA cannot distinguish active/LTBI; comprehensive approach required.
References: Indian Journal of Tuberculosis 2024, NTEP Studies India 2023.
