Tuberculosis is still active: A guide to symptoms and risks of TB infection

Tuberculosis (TB) is a serious infectious bacterial disease that mainly affects the lungs but can spread to other parts of the body. While cases of TB have declined over the past few decades, and the U.S. has one of the lowest rates of TB infection worldwide, recent reports from the Centers for Disease Control and Prevention (CDC) show that TB cases have been increasing in the U.S. since 2020. As infection rates continue to rise, knowing whether you’ve been exposed to TB is key to maintaining your health and safety.

If you’ve been exposed to TB or need to provide evidence of a negative TB test, it’s important to understand the disease and get a TB test. Here’s a guide to what TB is, what TB symptoms are and how you can check to see if you have been exposed to TB bacteria.

What is TB?

TB is caused by bacteria called Mycobacterium tuberculosis. When a person with active TB coughs, sneezes or speaks, they expel tiny droplets containing the bacteria into the air. If people in close proximity inhale these droplets, they may get infected.

Not everyone who is exposed will become infected, and not all who are infected will develop active TB. Approximately 90% of new TB cases result from latent TB infection, where the bacteria lie dormant in the body. People with latent TB present with no symptoms and cannot spread the bacteria. However, without treatment, latent TB can progress to active TB, which is when people show symptoms and can infect others around them.

Symptoms of active TB include:

• Persistent cough lasting three weeks or longer 
• Coughing up blood or phlegm from deep inside the lungs
• Chest pain
• Unintentional weight loss
• Loss of appetite
• Chills, fever and night sweats
• Fatigue
  
  

Although TB most commonly affects the lungs, in some cases, TB can also spread to other areas of the body like the kidneys, spine or brain.

Risk factors for TB include:

• Medical conditions that weaken the immune system (e.g., HIV/AIDS, diabetes, cancer)
• Residence or employment in a correctional facility or long-term care facility
• Substance use
• Homelessness
  
  

If you suspect that you may have been exposed to TB or are experiencing symptoms, you can reach out to a healthcare provider to determine next steps.

Types of TB tests

There are two types of TB tests available:

• Tuberculin skin test: It involves a trained healthcare personnel injecting a small amount of fluid (tuberculin) under the skin and checking for a reaction after 2-3 days. A raised bump at the injection site may indicate a TB infection
• TB blood test: It measures how strongly the immune system reacts to TB bacteria. The Labcorp OnDemand Tuberculosis (TB) Blood Test is an interferon-gamma release assay (IGRA) blood test that measures a person’s immune reactivity to M. tuberculosis. This blood test screens for TB but does not diagnose active TB disease or latent TB infection
  
  

Between the two types, a TB blood test may be a more convenient alternative, as it only requires a single blood draw. This can mean getting your results sooner without having to take a second trip to your provider’s office to read your skin test results. It’s also important to note that skin tests for TB can show a false-positive result if you have had a prior Bacille Calmette-Guérin (BCG) TB vaccination. The QuantiFERONTM TB Gold Plus test, available at Labcorp OnDemand, is recommended by the CDC as an alternative to the skin test in certain situations.

If you are concerned about your TB status, discuss the options with your healthcare provider, who can help you determine whether a skin or blood test to check for TB is right for you.

Who should get tested for TB?

The CDC recommends testing for certain higher-risk individuals, including:

• People who have spent time with someone known to have active TB disease
• Healthcare workers exposed on the job
• People immigrating from or traveling to parts of the world where TB is more common like Africa, Asia, Latin America and Eastern Europe
• Residents and employees of correctional facilities, homeless shelters and nursing homes
• People with health conditions such as HIV, diabetes or cancer
• People taking medications that weaken their immune system

Even if you don’t fall into a high-risk group, talk to your provider if you have any concerning symptoms. Catching TB early is critical and can prevent transmission to others.

When to get a TB test

Getting a TB test is important if you’ve been exposed to someone with active TB or are in the high-risk category of potentially contracting TB infection. Knowing your status allows you to take steps to protect your health and avoid spreading it to others.

If you’re wondering where to get a TB test, you can purchase a test online, go to your local Labcorp patient service center for sample collection and access your results online in your Labcorp PatientTM account.

Note: This screening test is not intended to be used to diagnose a latent TB infection or active TB disease. This test isn’t recommended for people with any active TB symptoms such as a cough for more than two weeks, fevers, night sweats or weight loss. You should contact your provider for the next steps if you have these symptoms.