PPD Test: Full Form and Explanation
The PPD Test stands for Purified Protein Derivative Test. It is primarily used to determine if a person has been exposed to Mycobacterium tuberculosis, the bacterium that causes tuberculosis (TB).
Key Points About the PPD Test:
- Purpose:
The PPD test is used for screening individuals for latent or active tuberculosis infection.
Procedure:
- A small amount of purified protein derivative is injected just under the skin (intradermally) typically on the forearm.
After 48 to 72 hours, the injection site is examined for a reaction.
Interpretation of Results:
- Positive Reaction: Indicates likely exposure to TB. Further diagnostic tests may be needed to confirm active TB.
Negative Reaction: Generally indicates no exposure to TB, but false negatives can occur, especially in individuals with weakened immune systems.
Important Considerations:
- Risk Factors: Individuals with certain risk factors (e.g., history of TB exposure, weakened immune system, recent travel to high-risk areas) should be tested.
- Limitations: The PPD test cannot differentiate between latent TB infection and active TB disease.
Understanding the PPD Test is essential for public health, especially in controlling and preventing the spread of tuberculosis. It is a simple and effective tool in the healthcare setting for TB screening.