Purified Protein Derivative (PPD)
Definition - What does Purified Protein Derivative (PPD) mean?
A purified protein derivative (PPD) is an extract of a specific pathogen called tuberculin, which is a viral agent originating from mycobacterium tuberculosis, more commonly identified as tuberculosis. It is an infectious airborne disease capable of being transmitted from one affected party to another via inhalation. As a safety measure, tests are administered to people to confirm whether immunity against the tuberculosis virus exists.
WorkplaceTesting explains Purified Protein Derivative (PPD)
Purified protein derivative (PPD) pertains to an extract of a microbe called tuberculin, which is the viral agent comprising mycobacterium tuberculosis, referred commonly to as tuberculosis. Although, the tuberculosis contagion and its potentially life-threatening effects can remain latent for years, tuberculin purified protein derivative tests are administered to patients in order to verify whether the tuberculosis disease is, in fact, present in the body. A person’s biochemical reaction in response to a material placed under the skin in the forearm, also known as the Mantoux test, is determined by a relative small welt that forms at the injection/scratch site.
A doctor then reexamines the area within a designated time frame (usually after 48-72 hours) observing the skin for any adverse reactions distinguishing between either positive and negative test results. Redness is not measured as a result in the test. Raised, hard skin is measured for toughness and diameter. The exact numbers needed to be considered positive depends on a number of factors and the local risk of infection.