NHA Certified Clinical Medical Assistant (CCMA)Foundational Knowledge and Basic ScienceHard
A medical assistant is preparing to administer an intramuscular injection to an adult patient. The medication is highly viscous. Which of the following needle gauge ranges would be most appropriate for this type of medication?
- A25-27 gauge
- B30-31 gauge
- C18-20 gauge
- D22-23 gauge
Show answer & explanationAnswer & explanation
Correct answer: C. 18-20 gauge
Highly viscous medications require a larger needle lumen to pass through easily. A lower gauge number indicates a larger needle diameter. Therefore, 18-20 gauge needles are suitable for viscous solutions.
Why the other options are wrong
- A. 25-27 gauge needles are smaller and typically used for subcutaneous or intradermal injections, or less viscous IM medications.
- B. 30-31 gauge needles are very fine and used for delicate injections like insulin or intradermal, unsuitable for viscous IM medications.
- D. 22-23 gauge needles are common for average IM injections, but may be too small for highly viscous medications.
Needle Gauge for Viscosity
Needle gauge refers to the diameter of the needle lumen. A lower gauge number indicates a larger diameter, which is necessary for administering viscous medications.
- Lower gauge = larger needle diameter.
- Higher gauge = smaller needle diameter.
- Viscous medications require larger diameter needles (lower gauge).
Memory trick: Gauge Goes Down, Flow Goes Up