NHA Certified Clinical Medical Assistant (CCMA)Clinical Patient CareMedium
A medical assistant is preparing to perform a capillary puncture on an adult patient. Which of the following fingers is the most appropriate site for collection?
- AIndex finger
- BThumb
- CMiddle finger
- DPinky finger
Show answer & explanationAnswer & explanation
Correct answer: C. Middle finger
The middle finger (or ring finger) is the preferred site for capillary puncture in adults because it usually has adequate tissue depth, good capillary supply, and is less sensitive than the index finger.
Why the other options are wrong
- A. The index finger is often more sensitive and calloused, and it is used for many daily activities, making it less ideal.
- B. The thumb is generally too calloused and has a pulse, making it unsuitable for capillary puncture.
- D. The pinky finger has less tissue and is closer to bone, increasing the risk of injury and inadequate blood flow.
Capillary Puncture Sites (Adult)
For adult capillary punctures, the lateral sides of the third (middle) or fourth (ring) fingers are preferred due to good blood supply and reduced risk of injury.
- Preferred: middle or ring finger.
- Puncture site: lateral sides of fingertip.
- Avoid: thumb, index, pinky, central tip.
- Ensure adequate blood flow.
Memory trick: Middle or Ring: Right for Bing!