Latent tuberculosis testing through the ages: the search for a sleeping killer

Area of Science:

• Medical Microbiology
• Infectious Diseases
• Diagnostic Immunology

Background:

• Tuberculosis (TB) has a long history, with its cause remaining unknown for millennia.
• Robert Koch identified Mycobacterium tuberculosis and developed Old Tuberculin for TB diagnosis.
• Early diagnostic efforts paved the way for advancements in TB testing.

Purpose of the Study:

• To trace the historical development of tuberculosis diagnostic tools.
• To highlight key figures and their contributions to TB diagnostics.
• To compare traditional and modern methods for detecting TB infection.

Main Methods:

• Historical review of tuberculosis diagnostic methods.
• Description of the evolution from Old Tuberculin to Purified Protein Derivative (PPD) tuberculin.
• Introduction of Interferon-γ Release Assays (IGRAs) as modern alternatives.

Main Results:

• Old Tuberculin's diagnostic potential led to improved tests like the Tuberculin Skin Test (TST).
• Florence Seibert developed Purified Protein Derivative (PPD) tuberculin, the current standard for TST.
• IGRAs offer an alternative to TST for detecting latent TB infection.

Conclusions:

• TST and IGRAs are valuable for identifying M. tuberculosis infection.
• Neither TST nor IGRA can predict progression to active tuberculosis.
• Diagnosis of active TB requires clinical symptoms, imaging, and culture.