In medicine, some blood tests are conducted on venous blood obtained by fingerstick (or fingerprick) (or, for neonates, by an analogous heelprick). The site, free of surface arterial flow, where the blood is to be collected is sterilized with a topical germicide, and the skin pierced with a sterile lancet. After a droplet has formed, venous blood is captured in a capillary tube (usually relying on surface tension).

In medicine, some blood tests are conducted on venous blood obtained by fingerstick (or fingerprick) (or, for neonates, by an analogous heelprick). The site, free of surface arterial flow, where the blood is to be collected is sterilized with a topical germicide, and the skin pierced with a sterile lancet. After a droplet has formed, venous blood is captured in a capillary tube (usually relying on surface tension).