What It Is
The Mantoux test is a skin test used to check whether a person's immune system has previously been exposed to the bacteria that causes tuberculosis.
What It Checks
The Mantoux test measures the immune system's response to a small amount of purified protein derived from the tuberculosis bacteria, injected just under the skin. A certain type of skin reaction at the injection site suggests the immune system has encountered this bacteria at some point, either through past infection or, in some cases, prior vaccination.
Why It's Used
The Mantoux test is commonly used to screen for past or current tuberculosis infection, particularly in people who may have been exposed, those with certain risk factors, or as part of routine screening in specific settings.
How It's Done
For the Mantoux test, a small amount of testing fluid is injected just beneath the surface of the skin, typically on the forearm, creating a small raised bump at the injection site. The person returns after a set period, usually 48 to 72 hours, so that a trained healthcare provider can measure any resulting skin reaction, specifically the size of any firm swelling that has developed at the site, rather than simply redness alone.
Background
The Mantoux test is named after a French physician who developed the technique in the early 20th century, building on earlier tuberculin testing methods developed by other researchers investigating tuberculosis in the late 19th century. It became a widely used, standardized method for tuberculosis screening through much of the 20th century, and while newer blood-based tests have since become available as an alternative in some settings, the Mantoux test remains a commonly used screening method today.