Capillary blood collection methods

Capillary blood collection plays a crucial role in obtaining small blood samples for various point-of-care testing and pediatric or geriatric patient populations. Phlebotomists must be proficient in capillary blood collection methods to ensure accurate specimen acquisition while prioritizing patient comfort and safety.

Fingerstick Technique

The fingerstick technique involves puncturing the fingertip (usually the middle or ring finger) to obtain capillary blood samples. Phlebotomists should carefully select an appropriate site on the finger, typically avoiding the thumb and index finger due to their increased sensitivity. Utilizing a lancet device set to an appropriate depth, the phlebotomist creates a small puncture, allowing blood to form a small bead on the fingertip. Proper technique and consistent application of the lancet can minimize patient discomfort and reduce the risk of inadequate sample volumes.

Heelstick Technique

Primarily utilized for neonatal and pediatric patients, the heelstick technique involves puncturing the infant’s heel to obtain capillary blood samples. Phlebotomists must exercise exceptional care and precision when performing heelsticks, selecting the lateral or medial plantar surface of the heel to minimize the risk of injury to bone or other structures. The use of a gentle, but firm, pressure to aid blood flow and prompt sample collection is essential to ensure a successful and safe procedure.

Capillary Collection Devices

Microcollection tubes, capillary tubes, or specialized capillary blood collection devices may be employed to facilitate the collection and transfer of capillary blood samples for laboratory analysis. Phlebotomists must be skilled in the proper handling and filling of these devices, ensuring the collection of adequate sample volumes and the prevention of hemolysis or contamination during the transfer process.

References:

  • Clinical and Laboratory Standards Institute. (2008). Procedures and Devices for the Collection of Diagnostic Capillary Blood Specimens; Approved Standard—Seventh Edition.
  • World Health Organization. (2010). WHO Guidelines on Drawing Blood: Best Practices in Phlebotomy.