Blood-tests Explained


Disclaimer:

This website is intended to assist with patient education and should not be used as a diagnostic, treatment or prescription service, forum or platform. Always consult your own healthcare practitioner for a more personalised and detailed opinion

Potassium


At a Glance

Why Get Tested?

To determine whether your potassium level is within normal limits; to help evaluate electrolyte balance; to help determine the cause of and monitor treatment for illnesses associated with abnormal potassium levels in the body

When to Get Tested?

When you have symptoms such as muscle weakness and/or irregular heart beat (cardiac arrhythmia) or when an electrolyte imbalance is suspected; at regular intervals when you are taking a medication and/or have a disease or condition, such as high blood pressure (hypertension) or kidney disease, that can affect your potassium level; as part of a routine medical exam

Sample Required?

A blood sample drawn from a vein in your arm; sometimes a random or 24-hour urine sample

Test Preparation Needed?

None

The Test Sample

What is being tested?

Potassium is an electrolyte that is vital to cell metabolism. It helps transport nutrients into cells and removes waste products out of cells. It is also important in muscle function, helping to transmit messages between nerves and muscles. This test measures the amount of potassium in the blood and/or urine.

Potassium, along with other electrolytes such as sodium, chloride, and )2bicarbonate (total CO, helps regulate the amount of fluid in the body and maintains a stable acid-base balance. Potassium is present in all body fluids, but most potassium is found within the cells. Only a small amount is present in fluids outside the cells and in the liquid part of the blood (called serum or plasma).

We get most of the potassium we need from the foods that we eat and most people have an adequate intake of potassium. The body uses what it requires and the kidneys eliminate the rest in the urine. The body tries to keep the blood potassium level within a very narrow range. Levels are mainly controlled by aldosterone, a hormone produced by the adrenal glands in the kidneys.

Because the blood concentration of potassium is so small, minor changes can have significant consequences. If potassium levels are too low or too high, there can be serious health consequences; a person may be at risk for developing shock, respiratory failure, or heart rhythm disturbances. An abnormal potassium level can alter the function of the nerves and muscles; for example, the heart muscle may 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. Potassium can also be measured in a random or 24-hour urine sample.

Is any test preparation needed to ensure the quality of the sample?

No test preparation is needed.

The Test