Fingerpricks and heelpricks are used to obtain venous blood for some blood tests. In this process various methods are used to open a small superficial wound which produces no more than a few drops of blood. The procedure can be painful, but may be quicker and less distressing than venipuncture.

After a droplet has formed, venous blood is sucked up by a capillary (a thin glass tube), usually passively or sometimes by indirect suction.

Tests commonly conducted on capillary blood are:

• glucose levels - diabetics often have a portable blood meter to check on their blood sugar.
• mononucleosis - fingerprick testing can be used to test for mononucleosis
• hemoglobin levels - fingerprick testing of hemoglobin is a quick screening procedure to check if a blood donor or plasma donor has a high enough blood count to be allowed to donate blood or blood components.
• genetic testing - heelprick testing of a newborn's DNA allows for early diagnosis and mitigation of common hereditary disorders.

Fingerpricks are sometimes done on children and the elderly, when only a small amount of blood (less than 500 μg) is needed for a test. Neonates (newborn babies) are given heelpricks instead, as this is less likely to cause permanent damage (and because babies have very small fingers).

[edit] External links

• performing a fingerstick
• Heelpricks (see section "Blood collection on babies")