Neonatal sampling essentials
Collecting a heel capillary blood sample
Collection procedure for heel 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)
- Hold the foot with your thumb placed along its length being careful to avoid bending the foot back towards the shin, which could cause injury
- Gently massage along the length of the foot towards the heel using a light squeeze-and- release motion to allow large droplets of blood to form and encourage continuous blood flow2
- If you are using blood collection paper allow a large drop to form. Carefully fill each circle from the front side of the card using only a single drop of blood. Avoid touching the heel to the blood collection paper while applying blood to the circle
- If you are using a capillary tube hold one end horizontally and touch it to the blood droplets at the puncture site. Fill the tube while trying to minimise air infiltration and air bubbles in the tube. Gently massage the heel to maintain a continuous blood flow. When sufficient blood has been collected, place caps on both ends of the tube to allow for mixing and to minimise air contamination
- Alternatively, you may need to collect the sample in a specially-designed blood collection tube by allowing blood droplets to drip and flow into the tube by natural capillary action. It is also important not to use a scraping or scooping motion here
Avoid squeezing the heel 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.