Adult & paediatric sampling essentials
Collecting a finger capillary blood sample
Collection procedure for finger samples
- After puncturing the skin, use clean gauze to wipe away the first drop of blood to avoid specimen dilution with interstitial fluid1,2 (test dependent)
- With the patient’s hand pointing downward, firmly grasp the finger towards the base with your thumb placed along the length of the patient’s finger
- Gently massage along the length of the finger towards the tip, using a light squeeze-and- release motion to allow large droplets of blood to form and encourage continuous blood flow2
- If using a blood collection tube, place it vertically beneath the puncture site, and allow droplets to flow freely into the tube using gravity (A). Allow the next drop to form and drip into the container. Repeat until the tube is filled to the level required for testing; over-filling or under- filling may lead to inaccurate results2
- Attach the top of the specimen tube/container and gently mix the contents by swirling and inverting (gently turning upside down)
- If using a capillary tube or pipette allow a large drop of blood to form, position the device horizontally, and lightly touch the drop of blood (avoid touching the skin); allow the blood drop to be drawn into the collection vessel by capillary action (B) (avoid air bubbles)
Avoid squeezing the finger too hard or using a scraping or scooping motion while collecting blood, which could haemolyse the specimen and lead to inaccurate results and/or specimen rejection1,2
These materials have been produced in consultation with key opinion leaders and follow global guidelines, but the user should use his or her professional judgement when using any technique or method described in these materials and should take into account all applicable national, regional and institutional guidelines and regulations.
1. WHO guidelines on drawing blood: best practices in phlebotomy. World Health Organisation; 2010. 2. Clinical and Laboratory Standards Institute (CLSI) document GP42-A6 (former H04-A6): Procedures and Devices for the Collection of Diagnostic Capillary Blood Specimens; Approved Standard – Sixth Edition. Clinical and Laboratory Standards Institute; Wayne, Pennsylvania, USA: 2008.