Tine test

The tine test is a multiple puncture skin test used to determine if someone has been infected with Mycobacterium tuberculosis, the bacteria that causes tuberculosis (TB). It is a type of tuberculin skin test (TST), similar to the Mantoux test, but employs a device with multiple tines (small prongs) coated with tuberculin.

Procedure:

The tine test involves pressing the device with its tuberculin-coated tines into the skin, usually on the forearm. This introduces a small amount of tuberculin purified protein derivative (PPD) into the skin.

Interpretation:

The test site is examined 48 to 72 hours after application. The reaction is assessed based on the size of the induration (a raised, hardened area) around the puncture sites. A positive result indicates that the person has likely been infected with M. tuberculosis at some point in the past. The specific criteria for a positive result depend on factors such as the person's risk of TB exposure, underlying medical conditions, and BCG vaccination history. It is important to note that a positive tine test does not necessarily mean the person has active TB disease; it only indicates prior infection. Further testing, such as a chest X-ray and sputum cultures, is required to confirm active TB.

A negative result generally indicates that the person has not been infected with M. tuberculosis. However, a negative result can also occur in individuals who are immunocompromised or who have recently been infected but have not yet developed a detectable immune response.

Advantages and Disadvantages:

Advantages: The tine test is generally considered easier and quicker to administer than the Mantoux test.

Disadvantages: The tine test is considered less accurate than the Mantoux test. The amount of tuberculin delivered by the tine test can vary, making interpretation less precise. It is more prone to false-negative results, particularly in individuals with weaker immune systems. Because of its lower accuracy, the Mantoux test is often preferred, especially in high-risk populations.