What is the medical term for the procedure that removes the fluid from a joint for diagnostic purposes?

The procedure that removes fluid from a joint for diagnostic purposes is known as arthrocentesis. This minimally invasive technique involves inserting a needle into the joint space to withdraw excess synovial fluid, which can then be analyzed to identify the presence of infection, inflammation, or other medical conditions affecting the joint.

Arthrocentesis is commonly used to diagnose conditions like gout, arthritis, and joint infections. The fluid obtained can be examined under a microscope or sent for laboratory tests to assess its characteristics. This procedure not only provides diagnostic information but can also relieve pain and swelling in the joint by reducing pressure.

Other options such as arthroplasty, arthroscopy, and arthrotomy refer to different surgical procedures related to joints. Arthroplasty involves reconstructing or replacing a joint, arthroscopy is a procedure that allows direct visualization of a joint through a small incision using a camera, and arthrotomy refers to a larger surgical incision made to access a joint. Thus, these terms describe procedures distinct from the diagnostic purpose served by arthrocentesis.