The abbreviation I&O stands for which of the following?

• A. Input and Output
• B. Inlet and Outlet
• C. Intake and Output
• D. Ingestion and Output

Answer: (C)

Tracking fluid balance is essential in caregiving. I&O stands for Intake and Output, the standard way clinicians document how much fluid a person takes in and how much leaves the body. Intake includes all fluids a person consumes—drinks, soups, IV fluids, and tube feeds—while output includes urine, stool, vomit, wound drainage, and other losses. This pairing is used because it directly reflects hydration status and kidney function. Other pairings like Input and Output, Inlet and Outlet, or Ingestion and Output are not used in clinical records for this purpose, since intake is the preferred term for all forms of intake and ingestion emphasizes eating rather than overall fluids.