Test of tuberculosis: a fundamental step in the control of the disease


Test of tuberculosis have such a great importance for the proper management and sanitary control of the disease, which is why we bring you this information. Even so, it was in the 19th century that great progress was made in its understanding and care. In 1882, the German bacteriologist Robert Koch discovered the bacterium Mycobacterium tuberculosis, and proved that it was the cause of tuberculosis. This discovery allowed the development of more effective diagnostic test of tuberculosis and treatments. Despite advances in treatment, tuberculosis remains one of the world’s deadliest infectious diseases. According to the World Health Organization, around 10 million new cases of tuberculosis occur worldwide each year and an estimated 1.5 million people die from the disease. The fight against tuberculosis remains a global challenge, but significant advances have been made in the prevention, diagnosis and treatment of the disease.

Test of tuberculosis: what should you know before doing it?

There are two types of tests of tuberculosis to detect the infection: the tuberculin skin test and blood tests.

The person’s health care provider must choose which test will be used. Factors that determine which test will be used include why the person is getting the test, the availability of the test, and its cost. It is generally not recommended that a person have both tests (a tuberculin skin test and a blood test).

Test of tuberculosis

Tuberculosis as an infectious disease

It is caused by the bacterium Mycobacterium tuberculosis. It mainly affects the lungs, but it can also affect other organs in the body.

Tuberculosis is spread from person to person, through the air, when an infected person coughs, talks, or sneezes, and another person inhales the bacteria. That is why it is necessary to take a test of tuberculosis if you suspect you have the infection.

The tuberculin skin test

It is also called the Mantoux test, in fact, is one of the best test of tuberculosis. The tuberculin skin test requires two visits to the health care provider.

At the first visit the test is done and at the second visit the health care provider reviews your results.

  • The skin test is done by injecting a small amount of fluid called tuberculin into the skin on the lower arm.
  • The person receiving the tuberculin skin test should return within 48 to 72 hours to have the arm reaction examined by a trained health worker.
  • The result of this skin test depends on the size of the raised, hard, or swollen area.

Positive skin test reaction:

This means that the person’s body is infected with tuberculosis bacteria. More test of tuberculosis are needed to determine if the person has latent TB infection or TB disease.

Negative reaction to skin test:

This means that the person’s body has not reacted to the test, and they are not likely to have latent TB infection or TB disease. It can be repeated without problems, but if it is repeated, the new test must be done in another part of the body (for example, in the other arm).

It is the preferred test for detecting tuberculosis in children under five years of age.

Blood test to detect tuberculosis

In the range of the test of tuberculosis performed with blood, we have that’ve been approved by the US Food and Drug Administration (FDA) and are available in this country: the QuantiFERON®–TB Gold In-Tube test (QFT- GIT) and the T-SPOT®. TB (T-Spot).

Positive TB blood test result:

Means that the person has been infected with tuberculosis bacteria. More test of tuberculosis are needed to determine if the person has latent TB infection or TB disease.

Negative TB blood test result:

The person’s blood did not react to the test, and they are not likely to have latent TB infection or TB disease.

Blood tests for tuberculosis are the preferred tests to do in the following people:

  • People who have received the bacillus Calmette-Guérin (BCG) tuberculosis vaccine.
  • People who have difficulty returning for the second appointment to examine the reaction to the tuberculin skin test.

What are the symptoms of tuberculosis?

Tuberculosis can present with different symptoms, but in some cases, it may have no symptoms at all. The symptoms of tuberculosis can include:

  • Persistent cough lasting more than three weeks
  • Chest pain
  • Coughing up blood or bloody phlegm
  • Fatigue
  • Unintentional weight loss
  • Fever
  • Night sweats
Test of tuberculosis

If you have any of these symptoms, and you think you may have tuberculosis, it is important to seek immediate medical attention. Your doctor can do a detailed evaluation and run tests to determine if you have tuberculosis.

What kind of people are more frequent to get sick with tuberculosis?

Certain people should be tested for TB infection because they are at higher risk of being infected with the bacteria that cause it. Among these people are the following:

  • People who have spent time with someone who has TB disease.
  • People who come from a country where tuberculosis is common (most countries in Latin America and the Caribbean, Africa, Asia, Eastern Europe, and Russia).
  • Poblation who live or work in high-risk settings (for example, correctional facilities, long-term care facilities, or nursing homes and homeless shelters).
  • Health care workers caring for patients at increased risk of contracting tuberculosis disease.
  • Infants, children, and adolescents exposed to adults who are at increased risk for latent tuberculosis infection or tuberculosis disease

If tuberculosis is not treated, it can be a serious disease that can cause serious and life-threatening complications.

Therefore, it is important to seek medical attention if you suspect you have tuberculosis or have been in contact with someone who has tuberculosis.

Test of tuberculosis

Active tuberculosis

Usually,involves taking a combination of antibiotic medications for several months. It is important to take the medicines as directed, even if the symptoms disappear before the treatment is finished.

If treatment is stopped too soon, the bacteria can grow again and the tuberculosis can be more difficult to treat.

Latent tuberculosis

In the case of latent tuberculosis, the doctor may recommend taking medication for several months, to prevent the infection from becoming active in the future. It is important to follow the doctor’s recommendations to prevent further complications and to prevent the spread of the disease to others.

Many people who have latent TB infection never develop TB disease. But some people who have latent TB infection are more likely than others to have TB disease. People at high risk of developing tuberculosis disease include:

  • Poblation with HIV infection.
  • People who have been infected with tuberculosis bacteria in the last 2 years.
  • Babies and young children.
  • People who inject illicit drugs.
  • People who have other diseases that weaken the immune system.
    • Seniors.
  • People who in the past did not receive adequate treatment for tuberculosis.
  • People at low risk of infection with TB bacteria usually do not need to be screened.

A pregnant woman and her baby are at increased risk if tuberculosis disease is not diagnosed and treated.

A test of tuberculosis indicated for this case is the tuberculin skin test, because it is considered valid and safe throughout pregnancy. Blood tests for tuberculosis are also safe to use during pregnancy, but they have not been evaluated to diagnose tuberculosis infection in pregnant women. Other tests are needed to find out if a person has TB disease.

Test of tuberculosis

Here are some steps you can take to reduce your risk of contracting tuberculosis:

  1. Keep a good hygiene: Wash your hands frequently, especially after being in contact with someone who has a persistent cough.
  2. Avoid close contact with people who are sick with tuberculosis: If you know someone who has tuberculosis, try to keep a certain distance and avoid sharing personal belongings.
  3. Wear a mask: If you work in an environment where there are people with active tuberculosis, you may need to wear a special respiratory mask to reduce the risk of inhaling the bacteria.
  4. Maintain a healthy immune system: The immune system is important in fighting tuberculosis and other infections. Maintain a healthy lifestyle, eat a balanced diet, exercise regularly, and get enough sleep.
  5. If you are at risk of contracting tuberculosis, talk to a doctor: In some cases, it may be necessary to take preventive medicines to reduce the risk of contracting tuberculosis. A doctor can assess your risk and determine if you need to take these steps.

Remember that tuberculosis is a serious disease that can be successfully treated if detected early. If you have symptoms, see a doctor.

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