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A capillary sample is a blood sample collected by pricking the skin. Capillaries are tiny blood vessels near the surface of the skin.
Alternative NamesBlood sample - capillary; Fingerstick; Heelstick
How the test is performedSome blood tests are performed on blood obtained by pricking the skin of the finger, heel, or other areas and collecting a drop (or a few drops) of blood on a test strip or into a small container.
The area is cleansed with antiseptic and pricked with a sharp needle or a lancet. The blood may be collected in a pipette (small glass tube), on a slide, onto a test strip, or into a small container. Cotton or a bandage may be applied to the puncture site if there is any continued bleeding.
How the test will feelSome people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing.
Why the test is performedBlood transports oxygen, food, waste products, and other materials within the body. It also helps regulate body temperature. Blood is made up of a fluid called plasma and cells. Plasma contains various dissolved substances. The cellular portion consists primarily of red blood cells, but also includes white blood cells and platelets.
Because blood has multiple functions, tests on the blood or its components can provide valuable clues in the diagnosis of a multitude of medical conditions.
Capillary blood sampling offers several advantages:
- It is relatively easy to obtain (it can be difficult to obtain blood from the veins, especially in infants).
- There are several collection sites on the body (heel, fingertips, etc.) and these can be rotated.
- Testing can be performed at home and with minimal training. For example, diabetics must check their blood sugar several times a day using capillary blood sampling.
There are some disadvantages to capillary blood sampling.
- Only a limited amount of blood can be obtained using this method.
- There are some risks associated with the procedure (see below).
- Capillary blood sampling may provide inaccurate results, such as falsely elevated sugar, electrolyte, and blood count values.
See the specific test.
What abnormal results meanResults vary depending on the test performed.
What the risks are- Excessive bleeding
- Fainting or feeling light-headed
- Infection (a slight risk any time the skin is broken)
- Scarring (occurs when there have been multiple punctures in the same area)
- Calcified nodules (sometimes occurs in infants, but usually disappear by 30 months of age)
- Damage to blood cells from this method of collection can sometimes cause inaccurate test results (and the need to repeat the test with blood drawn from a vein)
Capillary blood sampling is very useful when very small amounts of blood are needed or when blood is very difficult to obtain, such as in infants. Many times, however, when a larger sample is needed, the blood must be obtained from a vein.
ReferencesBabar T, Skugor M. Endocrinology. In: Carey WD, ed. Cleveland Clinic: Current Clinical Medicine 2010. 2nd ed. Philadelphia, Pa: Saunders Elsevier; 2010:section 4.
Lewandrowski K. Point-of-care testing: an overview and a look to the future. Clin Lab Med. 2009 Sep;29(3):421-32.
Hayrapetian-Dorsi L. Genetics. In: Custer JW, Rau RE, eds. Johns Hopkins: The Harriet Lane Handbook. 18th ed. Philadelphia, Pa: Elsevier Mosby; 2009:chap 13.
Reviewed ByReview Date: 05/01/2011
Linda J. Vorvick, MD, Medical Director, MEDEX Northwest Division of Physician Assistant Studies, University of Washington, School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
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What steps can you take to determine the melting point of a substance that sublimes before it melts?
In such cases the melting point determination must be performed in a sealed capillary tube to avoid loss of sample. This can be achieved by heating the open end of the capillary tube, and with tweezers forcing it shut.
Why is it necessary to grind the sample in the recrystallization process?
Grinding the sample in the recrystallization process will allow for maximum exposure of particles in the original crystal. This will allow a more complete reaction and reformation of crystals that are more pure and stronger than before.
Does each sample have measurable mass?
The answer depends on sample of WHAT!
A sample collected by drilling into Earth's surface with a hollow drill and pulling out a column of soil and rocks?
a core sample
What property like volume depends of the size of the sample?
The volume and the mass of sample both depend on the size of the sample.A small sample has small volume and small mass, a big sample has big volumeand big mass. But the ratio of mass to volume is constant for a pure sample ofa substance, no matter what size the sample is. That ratio is called the densityof the substance.
What is a capillary melting point?
The sample is placed in a sealed capillary and heated up to the melting.
Why is it important to pack the sample tightly in the melting point capillary?
If left loose, the compound will be heated unevenly.
Why should each sample be tightly packet in melting poin tinto the capillary tube prior to heating?
It is Important to pack tightly in order to prevent the entrance of air into the capillary tube.
How do they test the coagulation time of a blood sample?
Testing the coagulation time of a blood sample can be done in a few ways. The first is simply to record the amount of time it takes a sample to clot manually.
What is capillary puncture?
capillary blood is the mixture of venous and arterial blood... A capillary sample is a blood sample collected by pricking the skin. Capillaries are tiny blood vessels near the surface of the skin.Capillary blood sampling offers several advantages:It is relatively easy to obtain (it can be difficult to obtain blood from the veins, especially in infants).There are several collection sites on the body (heel, fingertips, etc.) and these can be rotated.Testing can be performed at home and with minimal training. For example, diabetics must check their blood sugar several times a day using capillary blood sampling.
What steps can you take to determine the melting point of a substance that sublimes before it melts?
In such cases the melting point determination must be performed in a sealed capillary tube to avoid loss of sample. This can be achieved by heating the open end of the capillary tube, and with tweezers forcing it shut.
What is charging the chamber in a hemocytometer?
"Charging" simply means filling it with the sample. Pipette a small amount into the channel and allow it to be drawn up into the chamber by capillary action.
What are the steps involved in short tandem repeat?
There are about 5 steps that are involved in short tandem repeat. The 5 steps are DNA purification, Design primer, Sample preparation, Capillary electrophoresis and data analyzation.
What is another name for a test tube?
another name for test tube is culture tube or sample tube
Why is it important to pack the sublimate uniformly?
The melting point sample capillary tube has to be packed efficiently and uniformly, because air spaces can cause nonuniform heat transfer within the tube. This can inconsistency, with some parts of the sample melting before others, which results in poor reproducibility. A uniformly packed tube will melt consistently and evenly to give a sharp, reproducible melting point determination.
Explain 1 procedure used for obtaining HIV serostatus?
There are three methods used to determine the hiv sero status namely:Rapid test,Elisa Assay and unigold...rapid test involves use of a determiner(used to show wether blood is positive negative or invalid.)chase buffer(liquid substance that is added to blood sample)and capillary tube(caries sample blood from the finger)..once blood sample is placed on the determiner,one waits for about 5 minutes to obtain results
Difference between random sample and convenience sample?
random sample is a big sample and convenience sample is small sample
