What is the maximum recommended volume for the SC route?

• A. 0.5 mL
• B. 2 mL
• C. 1.3 mL
• D. 3 mL

Answer: (C)

Subcutaneous tissue has a limited capacity to hold injected fluid and relies on slower diffusion into nearby blood vessels for absorption. If too much fluid is injected, the tissue becomes distended, which can cause pain, leakage, and, with larger volumes, the dose may start to enter muscle rather than stay in the subcutaneous space, altering absorption. Because of this, the practical upper limit for a subcutaneous injection is about 1.3 mL. Smaller volumes like 0.5 mL are common for many drugs, while larger volumes such as 2 mL or 3 mL exceed the tissue’s capacity for reliable subcutaneous delivery and increase the risk of IM delivery and unpredictable absorption.