
In
medicine
Medicine is the science and Praxis (process), practice of caring for a patient, managing the diagnosis, prognosis, Preventive medicine, prevention, therapy, treatment, Palliative care, palliation of their injury or disease, and Health promotion ...
, some
blood test
A blood test is a laboratory analysis performed on a blood sample that is usually extracted from a vein in the arm using a hypodermic needle, or via fingerprick. Multiple tests for specific blood components, such as a glucose test or a ch ...
s are conducted on capillary 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
A topical medication is a medication that is applied to a particular place on or in the body. Most often topical medication means application to body surfaces such as the skin or mucous membranes to treat ailments via a large range of class ...
germicide, and the skin pierced with a sterile
lancet. After a droplet has formed,
capillary blood is captured in a
capillary tube (usually relying on
surface tension). Blood cells drawn from fingersticks have a tendency to undergo
hemolysis
Hemolysis or haemolysis (), also known by several other names, is the rupturing (lysis) of red blood cells (erythrocytes) and the release of their contents (cytoplasm) into surrounding fluid (e.g. blood plasma). Hemolysis may occur in vivo o ...
, especially if the finger is "milked" to obtain more blood.
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Uses
Tests commonly conducted on the
capillary blood collected are:
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Glucose
Glucose is a simple sugar with the molecular formula . Glucose is overall the most abundant monosaccharide, a subcategory of carbohydrates. Glucose is mainly made by plants and most algae during photosynthesis from water and carbon dioxide, usi ...
levels –
Diabetics often have a portable blood meter to check on their
blood sugar
Glycaemia, also known as blood sugar level, blood sugar concentration, or blood glucose level is the measure of glucose concentrated in the blood of humans or other animals. Approximately 4 grams of glucose, a simple sugar, is present in the blo ...
.
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Mononucleosis – Fingerstick testing can be used to test for mononucleosis.
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Hemoglobin
Hemoglobin (haemoglobin BrE) (from the Greek word αἷμα, ''haîma'' 'blood' + Latin ''globus'' 'ball, sphere' + ''-in'') (), abbreviated Hb or Hgb, is the iron-containing oxygen-transport metalloprotein present in red blood cells (erythrocyte ...
levels – Fingerstick testing of hemoglobin is a quick screening procedure to ensure a blood or
plasma donor
A donor in general is a person, organization or government which donates something voluntarily. The term is usually used to represent a form of pure altruism, but is sometimes used when the payment for a service is recognized by all parties as rep ...
has an acceptably high
blood count for
donating blood or blood components.
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Genetic testing
Genetic testing, also known as DNA testing, is used to identify changes in DNA sequence or chromosome structure. Genetic testing can also include measuring the results of genetic changes, such as RNA analysis as an output of gene expression, or ...
– Heelprick testing of a newborn's
DNA allows for early diagnosis and mitigation of common
hereditary disorders.
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CBC
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Prothrombin time
Fingersticks are routine for hardy adults, but are generally performed on children and the elderly only if a small amount of blood suffices for needed tests.
Neonates are given heelpricks instead, as this is less likely to cause permanent damage.
References
{{reflist
External links
Heelpricks section "Blood collection on babies"
Blood tests