Diagnosis of Tuberculosis Current concepts

Dr A D Deshpande MD (Micro) , MD (Patho)

WHO

Int. Std. of TB Care

Std. of TB Care in India

RNTCP

India (25%)

India = 1500 deaths / day because of Tuberculosis

DiagnosisDisease

60 days

15 New cases

Robert Koch

My name is Koch

World TB day 24 March

March 24 1882 -- Dr Robert Koch discovered TB bacillus

Lab Diagnosis of Tuberculosis

Microbiology Tests

Sputum for ZN stain Culture PCR based Tests

Sputum for ZN stain

2 Samples ( Sensitivity)

• LED microscope• Fluorescent

microscope

Sputum for ZN stain

Culture L J Medium BACTEC MGIT

Culture - BACTEC MGIT

Results : 15 days 42 days

Most Sensitive Test Antibiotic Sensitivity for full 13 drugs

Sample to be sent in Saline

• LINE PROBE ASSAY PCR REC BY RNTCP

• OTHER PCR TESTS DONE BY LABS LIKE RANBAXY AND METROPOLICE

( ALL THESE METHOD NOT VALIDATED BY WHO )

PCR Based Tests

PCR based Tests

Gene Xpert - Fast (90 mins) - Easy to perform - Genotypic Drug Resistance (Rif)- Dead Bacteria can

give Test positive

WHO endorsed Test, 2010

Extra pulmonary TB

Lymphnode – PusCSF Synovial fluidEndometrial tissuePleural fluidAny Pus

•BACTEC MGIT Culture & Sensitivity • Gene Xpert

First do smear for ZN stain

Cost - Subsidized Rates ~ IPAQT (Initiative for promoting Affordable & Quality tests)

• Gene Xpert : 2000 Rs

• Line probe Assay (for Sputum Positive samples Only Via RNTCP) : 1600 Rs

• BACTEC MGIT Culture : 900 Rs

Serum IgG , IgM for TB

by Govt. of India

7 June 2012

TB is a Notifiable Disease

Don’t send patients Blood to Diagnose TB

• Not recommended in Adults by RNTCP• Useful in Children

Tuberculin Test (Mantoux Test)

Tuberculin Test in Vitro = TB GoldSame are IGRA & Quantiferon tests

NOT RECOMMENDED IN ADULTS

TB GOLD is NOT Gold

Latent TB

• Child contacts• All Immunosuppressed – HIV Patients• In US

Diagnosis of Tuberculosis in Pathology

FNAC Histopathology

>15 Days Productive cough / Doubtful Radiological finding - Sputum for ZN stain

Culture (BACTEC MGIT) - Most Sensitive Gene Xpert – Fast No role of Tuberculin Test in Adults Blood is not a sample, Serology is Banned

Take Home Message

Thank you