What is psa?

"PSA" can refer to several different things, and context is important to provide accurate information. Here are a few interpretations:

1. Prostate-Specific Antigen (PSA) Test:

   • This is a blood test used primarily to screen for prostate cancer. The test measures the amount of prostate-specific antigen in the blood, which is a protein produced by both cancerous and noncancerous tissue in the prostate. Elevated levels may indicate prostate cancer, an enlarged prostate, or a prostate infection.

2. PSA Peugeot Citroën:

   • Historically, this was a French multinational automotive manufacturer, known for producing Peugeot and Citroën automobiles. It is now part of Stellantis, following a merger with Fiat Chrysler Automobiles in 2021.

3. Professional Sports Authenticator (PSA):

   • This is a company that provides grading services for collectible cards, autographs, and other memorabilia. PSA is well-known in the sports and collectibles industry for its authentication and grading services.

4. Public Service Announcement (PSA):

   • A PSA is a message distributed to the public to raise awareness and change public attitudes and behavior towards a social issue. These announcements can be delivered through various media, including television, radio, and online platforms.

5. Pressure Swing Adsorption (PSA):

   • A technology used to separate gases from a mixture under pressure, relying on the fact that different gases are attracted to solid surfaces (adsorbents) in different degrees. PSA is commonly used for the production of oxygen or nitrogen.

If you have a specific context or definition in mind, please let me know, and I can provide more detailed information!