At a Glance
Why Get Tested?
When to Get Tested?
As part of a routine medical examination or to investigate a serious illness, such as high blood pressure or kidney disease
A blood sample taken from a vein in the arm
Test Preparation Needed?
The Test Sample
What is being tested?
Potassium is present in all body fluids, but most potassium is within your cells, with only a very small amount in the serum or plasma component of the blood. If potassium goes too low or too high, your health may be impaired. An abnormal concentration can alter the function of the nerves and muscles; for example, in extreme cases you may experience heart rhythm disturbances or the heart muscle may even lose its ability to contract.
How is the sample collected for testing?
A blood sample is taken by needle from a vein in the arm.
NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.
Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.
Is any test preparation needed to ensure the quality of the sample?
No test preparation is needed.
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NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.