Thursday 19 November 2020

All You Need to Know About Types of Tuberculosis Tests

Tuberculosis is an infectious disease that affects the lungs and may even spread to other body parts. When it involves the lungs, then it is termed as pulmonary TB. And, when outside the lungs, then it is extrapulmonary TB. 

A guest post by Devin Hyatt.

Tuberculosis can be categorized as being latent or active TB.

Active TB is contagious, and the symptoms are severe, while latent TB is non-contagious and exhibits no symptoms. 

The Most Common Symptoms of Active Tuberculosis:

● Chills

● Fatigue

● Night Sweats

● Unexplained Weight Loss

● Loss of Appetite

● Fever

If untreated, active tuberculosis can be life-threatening.

But, if you’ve been diagnosed with latent tuberculosis, it tells that the bacteria of tuberculosis is there in the body, but it is not active. If you are not experiencing any symptoms, it means you’re not contagious.

Only 5 to 10% of latent tuberculosis cases translates into active tuberculosis, people with compromised immunity are at a higher risk, 

Now, Let’s Talk About the Different Types of Tuberculosis. 

Types of TB Tests

There are different tests to diagnose tuberculosis.

Firstly, your doctor will check for the swollen lymph nodes and listen to their patient’s breathing using a stethoscope.

Next, you’ll have to undergo a series of tests to confirm it and to determine if it is latent or active tuberculosis.


The ELISA test is a highly sensitive and reliable diagnostic tool for tuberculosis. The Elisa kit principle is to identify the IgG and IgM antibodies produced in the body in response to the foreign invasion.

The ELISA test for tuberculosis originated in the 1980s. Today, most doctors prescribe the ELISA test before a more-in-depth screening test. The test is straightforward; it involves taking the blood sample, and then sending it to a medical laboratory for analysis. The ELISA test result takes more than 24 hours if it is done locally. 

Mantoux Tuberculin Skin Test (TST)

In this type of TB test, a small amount of tuberculin is injected into the forearm’s skin. 

After injection, the skin is monitored for the next 24 to 72 hours. A positive skin test means the bacteria of TB is present in your body. Then, additional tests are required to determine whether it is active or latent.
Blood Tests

Blood tests not only help to determine TB but also tell if it is active or latent. The principle of every blood test is to identify the reaction of the body’s immune system to the invasion by the TB bacteria. The US Food and Drug Administration has approved two types of blood tests, which are:

● QuantiFERON-TB Gold In-Tube test (QFT-GIT).

● T-SPOT TB test (T-Spot).

Imaging Tests
If the skin test comes out to be positive, then your healthcare provider will advise you to take the CT-scan or chest x-ray. These tests determine any lump formation or changes in the lungs caused by the active TB. 

Sputum Tests

When someone coughs, sputum comes out ( which is a mucus fluid). Your healthcare provider will collect the mucus and analysis for various strains of TB bacteria, in addition to the antibiotic-resistant types.

The results of the sputum tests are quite helpful in deciding on the right course of the treatment.
The Bottom Line

There are several types of tests to diagnose TB. If you’ve any chance of being exposed to the TB-causing bacteria, then you must consult your healthcare provider. Tuberculosis can be life-threatening and needs to be diagnosed early. Most people with proper treatment can make a full recovery.

Posted by Dr. Tim Sandle, Pharmaceutical Microbiology Resources (

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