NHA Certified Phlebotomy Technician (CPT)Collection RoutineEasy
A phlebotomy technician is performing a capillary puncture on an adult patient for a routine CBC. Which of the following fingers is the most appropriate site for collection?
- AThumb
- BIndex finger
- CRing finger
- DLittle finger
Show answer & explanationAnswer & explanation
Correct answer: C. Ring finger
The ring finger (or middle finger) is the preferred site for adult capillary punctures. These fingers are generally less calloused and have good capillary beds, while avoiding the thumb (too thick), index finger (more nerve endings, often calloused), and little finger (thinner tissue, closer to bone).
Why the other options are wrong
- A. The thumb is too thick and muscular, making it difficult to obtain a proper puncture depth and increasing the risk of pain.
- B. The index finger is often more calloused from daily activities and has more nerve endings, making it more painful.
- D. The little finger has thinner tissue and is closer to the bone, increasing the risk of bone injury (osteomyelitis) with a puncture.
Adult Capillary Puncture Site
The preferred location for performing a capillary puncture on an adult, typically the fleshy pad of the middle or ring finger.
- Use the palmar surface of the distal phalanx of the middle or ring finger.
- Avoid the tip or very end of the finger.
- Puncture off-center, perpendicular to the fingerprint lines.
- Ensure adequate blood flow by warming the site if necessary.
Memory trick: Ring and middle, not the thumb or little, for a good finger stick.