Fingerprick
Encyclopedia
Fingersticks and heelpricks are small superficial wound
s that provide venous blood
for some blood test
s. Various methods are used to open the wound, which produces no more than a few drops of blood
. The procedure can be pain
ful, but is typically quicker and less distressing than venipuncture
.
After a droplet has formed, venous blood is sucked up in a capillary tube, usually relying on surface tension
, but sometimes by indirect suction.
Tests commonly conducted on capillary blood are:
Full CBC (complete blood count)
Fingersticks 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).
Wound
A wound is a type of injury in which skin is torn, cut or punctured , or where blunt force trauma causes a contusion . In pathology, it specifically refers to a sharp injury which damages the dermis of the skin.-Open:...
s that provide venous blood
Venous blood
Venous blood is deoxygenated blood in the circulatory system. It runs in the systemic veins from the organs to the heart. Deoxygenated blood is then pumped by the heart to lungs via the pulmonary arteries, one of the few arteries in the body that carries deoxygenated blood .Venous blood is...
for some blood test
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 needle, or via fingerprick....
s. Various methods are used to open the wound, which produces no more than a few drops of blood
Blood
Blood is a specialized bodily fluid in animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells....
. The procedure can be pain
Pain
Pain is an unpleasant sensation often caused by intense or damaging stimuli such as stubbing a toe, burning a finger, putting iodine on a cut, and bumping the "funny bone."...
ful, but is typically quicker and less distressing than venipuncture
Venipuncture
In medicine, venepuncture, venopuncture or venipuncture is the process of obtaining intravenous access for the purpose of intravenous therapy or for blood sampling of venous blood. This procedure is performed by medical laboratory scientists, medical practitioners, some EMTs, paramedics,...
.
After a droplet has formed, venous blood is sucked up in a capillary tube, usually relying on surface tension
Surface tension
Surface tension is a property of the surface of a liquid that allows it to resist an external force. It is revealed, for example, in floating of some objects on the surface of water, even though they are denser than water, and in the ability of some insects to run on the water surface...
, but sometimes by indirect suction.
Tests commonly conducted on capillary blood are:
- glucoseGlucoseGlucose is a simple sugar and an important carbohydrate in biology. Cells use it as the primary source of energy and a metabolic intermediate...
levels - diabeticsDiabetes mellitusDiabetes mellitus, often simply referred to as diabetes, is a group of metabolic diseases in which a person has high blood sugar, either because the body does not produce enough insulin, or because cells do not respond to the insulin that is produced...
often have a portable blood meter to check on their blood sugarBlood sugarThe blood sugar concentration or blood glucose level is the amount of glucose present in the blood of a human or animal. Normally in mammals, the body maintains the blood glucose level at a reference range between about 3.6 and 5.8 mM , or 64.8 and 104.4 mg/dL...
. - mononucleosisInfectious mononucleosisInfectious mononucleosis is an infectious, widespread viral...
- fingerstick testing can be used to test for mononucleosis - hemoglobinHemoglobinHemoglobin is the iron-containing oxygen-transport metalloprotein in the red blood cells of all vertebrates, with the exception of the fish family Channichthyidae, as well as the tissues of some invertebrates...
levels - fingerstick testing of hemoglobin is a quick screening procedure to check if a blood or plasmaBlood plasmaBlood plasma is the straw-colored liquid component of blood in which the blood cells in whole blood are normally suspended. It makes up about 55% of the total blood volume. It is the intravascular fluid part of extracellular fluid...
donorBlood donationA blood donation occurs when a person voluntarily has blood drawn and used for transfusions or made into medications by a process called fractionation....
has a high enough blood count to be allowed to donate blood or blood components. - genetic testingGenetic testingGenetic testing is among the newest and most sophisticated of techniques used to test for genetic disorders which involves direct examination of the DNA molecule itself. Other genetic tests include biochemical tests for such gene products as enzymes and other proteins and for microscopic...
- heelprick testing of a newborn's DNADNADeoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...
allows for early diagnosis and mitigation of common hereditary disorders.
Full CBC (complete blood count)
Fingersticks 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).
External links
- Heelpricks, section "Blood collection on babies"