Aspiration / tap Aspiration
A needle is used to draw fluid from a body space — a joint, the pleural cavity, the abdomen — for testing or to relieve pressure.
What it can show
The nature of the fluid: infection, blood, inflammatory fluid, abnormal cells. The analysis often changes management immediately.
What it cannot show
Speaks only about the fluid obtained, not about the surrounding tissue.
This is the half people skip. A normal result answers one question, not every question.
Tell the staff before you start
Blood thinners · bleeding disorders · skin infection at the puncture site · anaesthetic allergy.
Also bring the full list of every medicine and supplement you take. Things bought without a prescription belong on that list too.