Tuberculosis Symptoms and Diagnosis

What Are the Symptoms of TB?

A person with inactive TB (latent TB) will have no symptoms, however, without treatment they can develop active TB disease and become sick.

Symptoms of active TB disease depend on where in the body the TB germs are growing. TB germs that grow in the lungs can cause the following symptoms:

  • A bad cough that lasts more than three weeks
  • Chest pain
  • Coughing up blood or mucus (sputum)

Other symptoms of active TB disease may include:

  • Weakness or fatigue
  • Loss of appetite
  • Unintentional weight loss
  • Fever
  • Chills
  • Night sweats

What are Reasons Someone May Need a TB Test?

  • An individual has symptoms of TB disease.
  • An individual is exposed to someone who has active TB disease.
  • An individual has factors that put them at higher risk for developing active TB disease.
  • An individual has health screening requirements for employment, school, travel or immigration.

When to See A Health Care Provider

A person who suspects that they may have been exposed to TB should contact their health care provider or health department as soon as possible.

How Is TB Diagnosed?

A health care provider will start by collecting a patient history to determine if an individual may have been exposed to TB. During a physical exam, they will use a stethoscope to listen to the lungs and check the lymph nodes in the neck for swelling.

There are two types of tests for TB infection:

TB Blood Test:

  • Requires only one visit with a health care provider
  • Uses a blood sample to find out of there is TB infection  
  • Measures how the immune system reacts to the germs that cause TB

TB Skin Test:

  • Requires two visits with a health care provider
  • Includes an injection of a small amount of fluid into the arm
  • Measures the size of the bump or reaction from the injection (48-72 hours later)

What Do the Test Results Mean?

A positive test result for TB infection means there is TB germs in the body. A health care provider will do other tests to determine if it is inactive TB or active TB disease. These tests may include a chest x-ray and a test of the sputum (coughed-up mucus) for bacteria.

A negative test result for TB infection means inactive TB or active TB disease is unlikely, but a health care provider may do additional tests especially if:

  • An individual has symptoms of active TB disease, such as coughing, chest pain, fever, weight loss, or fatigue.
  • An individual has HIV.
  • An individual has recently been exposed to TB germs.

Reviewed and approved by the American Lung Association Scientific and Medical Editorial Review Panel.

Page last updated: January 30, 2025

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