Tuberculosis is one of the oldest known infectious diseases that is always a threat to human health. The disease is caused by Mycobacterium tuberculosis bacteria. This disease is the second leading cause of death from infectious diseases in the world after AIDS.

In the past years, with the discovery of antibiotics against tuberculosis, the disease was somewhat controlled and the number of deaths due to it decreased.

The most common source of infection is pulmonary tuberculosis patients who have not been treated. These people emit infectious particles in the air through coughing, sneezing, talking and flushing out and causing other people to become infected.

The most important way to prevent the spread of this disease, is to eliminate and control the infection. Using accurate and prompt diagnostic methods and timely and appropriate treatment for patients can help control the disease and spread it to others.

TB diagnostic methods
Phlegm smear

The best and least costly way to diagnose tuberculosis in suspected people is to perform phlebotomy tests. In this method, the specimen is collected and tested three times in 2 to 3 days. In most cases, if tuberculosis occurs, the tuberculosis will be seen under the microscope.


tuberculosis infection

How to collect samples?

1. It is better to have a morning and a fasting sample.

2. Before taking the sample, it is necessary to wash the mouth a few times with ordinary water, to breathe deeply from the nose, and for a moment keep your breath in the chest and deplete it with a deep coughing sputum into the corresponding container.

3. If the person can not collect the sample by coughing, it should use methods such as inhaling water vapor or spraying with diluted brine.

4. Be careful not to sample the mouth water, the mouth water is clear and watery, but the spatula has adhesion.

5. The minimum amount of smudge should be as much as a teaspoon.

6. Spread the specimen in a mouth-watered container and keep it at a refrigerated temperature.

7. Use a disposable gloves at all stages of sampling.

Tuberculin Skin Test (PPD)

A tuberculin skin test is done to examine the likelihood of a person’s contact with tuberculosis tuberculosis mycobacterium tuberculosis. The most commonly used tuberculin test is called Manto.

Tips that should be taken into account after a tuberculin skin test:

  • The test result should be read after 48 to 72 hours. Since the test is done in the body, it is clear that the person himself must go to the laboratory after 48 to 72 hours.
  • After the test, rigidity and redness appear in the skin of the injection area.
  • Do not induce itching at the injection site.
  • Do not wet the injection site for 24 to 72 hours and do not bathe during this time.
  • Injecting a low amount of tuberculin and injecting the test also results in a false negative test for tuberculin skin test.

Adenosine deaminase (ADA)

An enzyme that decomposes adenosine and converts it into inosine and doxy-itosin. This enzyme plays a role in the proliferation and differentiation of T lymphocytes. Measuring adenosine deaminase in body fluids is important for distinguishing healthy individuals from patients with tuberculosis.

After sampling, the sample should be immediately separated and stored in the freezer until the test is completed. The sample should not be frozen or debris.The hemolytic sample is not acceptable for this test.


  • HENRY’S Clinical Diagnosis and Management by Laboratory Methods 22 nd EDITION Richard A. McPherson, MD -2011
  • Mosby’s Manual of Diagnostic and Laboratory Tests, 4th Edition By Kathleen Deska Pagana, PhD, RN and Timothy J. Pagana, MD, FACS
  • Kasper DL. Harrison’s principles of internal medicine. 16th ed. New York: McGraw-Hill: 2005.
  • Fairbanks VF, Klee GG: Biochemical aspects of hematology. In Tietz Textbook of Clinical Chemistry. Third edition. Edited by CA Burtis, ER Ashwood, Philadelphia, WB Saunders Company, 1999, pp 1642-1646



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