A complete medical examination for the diagnosis of TB would include:

Physical Examination: It is conducted in order to check the patient’s general health and check other factors that could affect the treatment.

Chest X-ray: In active pulmonary Tuberculosis, infiltrates, consolidations or cavities are often spotted in the upper lungs, with or without mediastinal or hilar lymphadenopathy or pleural effusions. In disseminated TB it is common to find many tiny nodules throughout the lung fields. In HIV and other low immunity persons, any abnormality in the x-ray could indicate TB, or the x-ray could even appear entirely normal.

Chest X-rays may suggest TB, but are never diagnostic of TB. They are however used to rule out the possibility of TB in those patients who have tested positive to the tuberculin skin test but apart from that have no symptoms of the disease.

Abreugraphy: It is an alternative to the regular chest X-Ray. It is a small radiographic image. Though it has a limited resolution, it is sufficient for the diagnosis of tuberculosis. It is much cheaper than the X-Ray. The procedure died down a little due to the decrease of the disease but it is still used sometimes, such as for screening prisoners, immigrants etc.

Microbiological examination: The culturing of Mycobacterium tuberculosis organisms from a specimen taken from the patient is the only definite way of diagnosing TB.

If the patient is producing sputum, the sputum smears and cultures should be done for acid-fast bacilli. Fluorescence microscopy is the preferred method to go about this.

If no sputum is being produced, the specimen can be obtained by inducing sputum, genital warts, laryngeal swab, bronchoscopy with bronchoalveolar lavage, or fine needle aspiration of a collection.

There are other mycobacteria too which are acid-fast. If the smear is positive, PCR or gene probe tests can distinguish Mycobacterium tuberculosis from other mycobacteria. Even if the smear shows negative, TB is still not ruled out, and is only excluded once the cultures show negative too.

Tuberculin Skin Test: There are two available test-

An induration of the skin of more than 5-15 mm to 10 Mantoux units is considered to be a positive test for TB, indicating the presence of the TB infection.

Laboratory: There are a lot of difficulties in diagnosis through the Tuberculin skin test, and therefore many laboratory methods of diagnosis are expanding. These include-

Whenever someone is diagnosed with TB, everyone in close contact with them must be screened with the Tuberculin skin test and/or a chest x-ray since it is a highly contagious disease. Visit the dual diagnosis website.