What is a Tuberculosis Test, and Why is it Necessary?

Tuberculosis is a serious illness that can usually be cured as long as it is identified.

If you work in healthcare or seek employment at a healthcare facility, you’re likely familiar with the concept of getting tested for tuberculosis or TB. However, you may not be fully aware of why it’s necessary to get TB tested and why this is such a vital part of keeping the public healthy and well.

At Lompoc Valley Medical Center, we strive to keep our patients, their families, and our employees informed about all matters relating to their health. Tuberculosis represents a significant threat to people who are immunosuppressed, and even though its presence has been reduced in the US, it still exists at low levels.

Globally, an estimated 2 billion people (one-third of the world’s population) are infected with TB. In honor of World TB Day, which occurs annually on March 24, here’s what you need to know about tuberculosis and why it’s important to get the routine testing that is recommended by your employer or healthcare provider.

What is Tuberculosis?

You may be familiar with the classic depiction of TB in old movies—a person coughs into a handkerchief and then, removing it, sees blood. Tuberculosis is a bacterial infection caused by a type of bacteria known as Mycobacterium tuberculosis. It spreads in the air from one person to another. When you’re infected with tuberculosis, it usually infects your lungs; however, it can also affect other parts of your body, such as your kidneys.

Tuberculosis can be a tricky bacterial infection to detect because it’s very possible for you to be infected with TB and unaware of your condition. Many people who have this type of TB infection, known as a latent infection, will never go on to develop symptoms of the active disease. However, when sick with active tuberculosis, some characteristic symptoms include a chronic cough, chest pain, coughing up blood, weakness, weight loss, appetite loss, fever, chills, or night sweats. Tuberculosis can be a life-threatening disease for certain people, including those who have suppressed immune systems.

The History of Tuberculosis

The bacteria that causes tuberculosis was discovered in 1882; however, experts believe it has existed for 3 million years, and it may have been infecting humans for 9,000 years. Before discovering the TB bacteria, one in seven people died of TB in the United States, and it caused one-quarter of the deaths in Europe.

The TB-related public health initiatives that we have in place today exist because of the nature of tuberculosis infections. When a person has a latent TB infection, they typically are unaware because they have no symptoms. This means that if their infection becomes active and they develop a cough, they can easily spread the infection to other people unknowingly.

Luckily, there has been a significant amount of progress made in the US in the fight against TB. When the US Centers for Disease Control and Prevention (CDC) first began keeping track of TB cases in 1953, there were 84,304 nationwide cases—in 2020, there were only 8,916 reported cases among a much larger population. Still, there is work to be done in the fight against TB. The CDC aims to eliminate TB, with a mantra that “finding TB is the first step toward ending TB.”

Who Should Get Screened for Tuberculosis?

You can think of TB screening programs as ways for health experts to “hunt” for the disease. Finding a TB infection can help a person stay safe and get treated, and it can also reduce the spread of TB at a population level.

According to the CDC, you should get tested for TB if any of the following situations apply to you:

• You have spent time with someone who has known TB disease
• You are from a country where TB disease is more common (which includes most countries in Latin America, the Caribbean, Africa, Asia, Eastern Europe, and Russia)
• You who live or work in a high-risk setting where groups of people live together in close proximity, such as a correctional facility, long-term care facility, nursing home, or homeless shelter
• You are a health care worker who cares for patients at increased risk for TB disease, such as people with HIV, young children and the elderly, people who inject illegal drugs, people with suppressed immune systems, or people who’ve recently had a TB infection or who did not receive correct TB treatment

It’s particularly important for people who work in healthcare settings to understand the policies in place to help identify and prevent the spread of tuberculosis infection.

What Kind of Tuberculosis Tests are Available?

There are two basic types of tests available to screen for the presence of tuberculosis: a skin test or a blood test. If you have been recommended to have a TB test for your employment, it’s important to check and ensure that you receive a specific type of test that your employer desires.

A TB skin test, or TST, checks to see whether your body reacts to an injection underneath the surface of your skin. The TB test is “placed” by the healthcare provider, and then it must be “read” 48 to 72 hours later. Your healthcare provider will check if your skin has reacted by raising up. If your skin has raised up a certain amount, it may be considered a positive test, depending on your medical situation. If you receive a TB skin test, it generally requires two visits to a health lab.

A TB blood test, known as a QuantiFERON-TB Gold test or a T-SPOT test, uses a blood sample. It checks to see if your body’s immune cells have been infected with tuberculosis based on certain substances that they release. If you receive a TB blood test, it generally requires one visit to a health lab.

What Happens if a Tuberculosis Screening Test is Positive?

Whether you receive a TB skin test or a TB blood test, it’s vital to understand what your results mean. Neither type of test can distinguish between an active TB infection or a latent TB infection.

If you have a positive result on a skin test or a blood test, you will need to follow up. This follow-up care may include:

• A different type of TB test—if you had a positive skin test, you may require a blood test, as false-positive tests are possible, especially if you have been previously vaccinated against tuberculosis (this is not a common practice in the US, but TB vaccines are administered in other countries)
• A chest x-ray to assess for the presence of tuberculosis disease in your lungs
• A test of your sputum, urine, or other tissues

If you are found to have TB present in your lungs, but you’re not having any symptoms of TB (such as a cough, fatigue, or night sweats), then it’s likely you have a latent TB infection. Luckily, detecting TB at this stage can ensure that you receive antibiotic treatment and never progress to active TB disease.

How is Tuberculosis Treated?

It can be intimidating to find out that you have a latent TB infection after a routine screening test. However, effective medications can treat and cure your infection and make sure that you do not develop active TB disease. Historically, people had to take antibiotics for 6 to 9 months to treat a latent TB infection. However, thanks to medical advancements, it’s now possible to have a shorter course of antibiotics, spanning just 3 to 4 months.

The antibiotic medications used to treat TB vary depending on your medical situation, but often you will be recommended to take more than one. This can reduce the chance that the bacteria become resistant to the medication. When you have a latent TB infection and do not have any symptoms, it may feel strange to take several different antibiotics for a prolonged period because you don’t feel sick in the first place. You may be tempted to stop taking your antibiotics before the course has finished; however, this can be very dangerous and worsen your infection.

Make sure that you understand exactly how to take your medication and for how long to ensure that you are properly treated and do not have any future difficulties stemming from TB.

How to Learn More About Tuberculosis Screening and Management

Tuberculosis had a big part in the history of our country, and it is still present and posing a threat. To stop the infection once and for all, it’s critical to screen for TB illness and treat any infections found. That’s why it’s imperative to follow the recommendations following tuberculosis screening to reduce your risk of personal illness and decrease the chance of you unintentionally passing TB along to others.

At Lompoc Valley Medical Center, our primary care providers and specialists can help you navigate the tuberculosis screening process, provide further management if you test positive, and treat you with medications if necessary.

To learn more about our services, contact us today.