Potassium (K) in Blood A potassium test checks how much
potassium is in the blood. Potassium is both an Reference
electrolyte Opens New Window and a mineral. It helps keep the
water (the amount of fluid inside and outside the body's cells)
and electrolyte balance of the body. Potassium is also important
in how nerves and muscles work. Potassium levels often change
with sodium levels. When sodium levels go up, potassium levels
go down, and when sodium levels go down, potassium levels go up.
Potassium levels are also affected by a hormone called
aldosterone, which is made by the Reference adrenal glands Opens
New Window. Potassium levels can be affected by how the
Reference kidneys Opens New Window Reference Opens New Window
are working, the blood Reference pH Opens New Window, the amount
of potassium you eat, the Reference hormone Opens New Window
levels in your body, severe vomiting, and taking certain
medicines, such as Reference diuretics Opens New Window and
potassium supplements. Certain cancer treatments