How to test for tuberculosis

Written by Wang Xiang Yu
Pulmonology
Updated on March 09, 2025
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To examine pulmonary tuberculosis, it is essential to understand that it pertains to tuberculosis changes in the lung tissue, airways, bronchi, and pleura. The pathogen causing tuberculosis is Mycobacterium tuberculosis, also known as the tubercle bacillus. There are multiple tests available for people with pulmonary tuberculosis, as the disease can vary based on location and type. Therefore, such patients generally require numerous tests.

The most commonly used are imaging studies for the chest, including X-rays and CT scans. In imaging studies, most patients will show some lesions, but there are instances where tuberculosis in the airways and bronchi might not be clearly visible on CT or X-rays, necessitating more invasive tests like bronchoscopy. Additionally, bacteriological examinations, such as sputum smear and pleural fluid smear, as well as culture for Mycobacterium tuberculosis, are typically conducted for patients.

Nowadays, hospitals equipped with the necessary facilities conduct molecular biological tests, namely nucleic acid testing for Mycobacterium tuberculosis DNA. Furthermore, some patients with complex conditions may require a histopathological biopsy, commonly referred to as tissue sampling, at the site of the lesion to observe under a microscope for characteristic changes indicative of tuberculosis. There are also immunological tests that assist in diagnosing tuberculosis, such as the gamma interferon release assay (commonly known as the T-SPOT), tuberculin skin test, and traditional antibody tests against Mycobacterium tuberculosis.

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Written by Han Jian Hua
Infectious Disease
1min 31sec home-news-image

Does tuberculosis infect people?

Tuberculosis is a contagious disease, and hearing the term "tuberculosis" inevitably makes people nervous. However, not all tuberculosis patients are contagious. Research shows that among tuberculosis patients, only those who have tuberculosis bacteria found in sputum smear tests are contagious. With a source of infection, the tuberculosis bacteria must be transmitted to others through certain routes. Airborne transmission is the main route of transmission for tuberculosis bacteria. When a tuberculosis patient coughs, sneezes, or speaks loudly, they release a large number of droplet nuclei containing tuberculosis bacteria into the air, which can be inhaled by healthy individuals and cause infection. The degree of tuberculosis bacteria infection mainly depends on factors such as the amount of bacteria the patient expels, the severity of coughing symptoms, and the extent of contact. Therefore, when there is a tuberculosis patient nearby, we first need to understand whether they are in the active phase of the disease, that is, expelling bacteria, and whether they are undergoing anti-tuberculosis chemotherapy. If the patient has a negative sputum test or has undergone chemotherapy for a positive sputum test, such patients have very low contagiousness, so there is no need to worry too much about being infected.

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Written by Wang Xiang Yu
Pulmonology
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Can tuberculosis be fatal?

Can tuberculosis be fatal? Of course, the answer is yes. Many diseases can lead to death, even a common cold can potentially result in death, let alone tuberculosis, which is an extraordinary illness. Currently, the mortality rate for tuberculosis patients is relatively low because the treatment for tuberculosis has improved significantly compared to the past. However, there are still a small number of patients who, due to untimely treatment of tuberculosis, discontinuation of medications on their own accord or non-compliance with medical advice, or who have other serious underlying diseases, may not tolerate the tuberculosis treatment. As a result, they could potentially die from adverse reactions to the tuberculosis medications.

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Written by Wang Xiang Yu
Pulmonology
1min 10sec home-news-image

Can tuberculosis be cured completely?

Whether tuberculosis can be completely cured varies from person to person. Most cases of tuberculosis, especially initial occurrences of pulmonary tuberculosis, can be cured in more than 80 to 90 percent of patients if they undergo standardized anti-tuberculosis treatment. However, it is essential that the treatment is standardized; it is not appropriate to simply take medication for one or two months and then stop when symptoms seem to disappear. The treatment duration for pulmonary tuberculosis is considered to be at least six months, and for some patients, it may even extend to a year. However, not all cases of pulmonary tuberculosis can be completely cured. A small percentage of patients may not achieve complete eradication due to resistance to tuberculosis bacteria or intolerance to the side effects of tuberculosis medications. In such cases, the prognosis might be poor, and some individuals may succumb to tuberculosis due to these factors.

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Written by Wang Xiang Yu
Pulmonology
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Does tuberculosis cause fever?

Does tuberculosis cause fever? The answer is definitely yes. Fever is one of the most common clinical manifestations of tuberculosis. Many tuberculosis patients experience low fevers, and a minority of patients, such as those with caseous tuberculosis or tuberculous pleurisy, may experience high fevers that can recur and persist. Moreover, tuberculosis patients may sometimes also have concurrent bacterial infections, which can cause the fever to last longer and be more difficult to control.

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Written by Xiong Hong Hai
Infectious Disease
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Does tuberculosis cause a runny nose?

Individuals with tuberculosis, if accompanied by a cold and rhinitis, will also experience a runny nose. However, simple tuberculosis, without any upper respiratory infections or rhinitis, does not lead to a runny nose. Therefore, it is important to accurately analyze the issue. Common symptoms of tuberculosis include persistent coughing, coughing up phlegm, low-grade fever, night sweats, bloody sputum, chest tightness, and difficulty breathing, among others. Once tuberculosis is definitively diagnosed, it is essential to commence timely and scientifically sound anti-tuberculosis treatments. Most cases can be completely cured.