Potassium (K)
Electrolytes & minerals ·Also called: K, potassium, serum potassium, hyperkalaemia, hypokalaemia
What it is
Almost all of the body's potassium sits inside cells, so the small amount measured in blood is a tightly controlled fraction of the total. The kidneys do most of the regulating, which is why kidney problems and urinary blockages disturb it so readily.
Why your vet measures it
Heart muscle depends on a stable potassium level to conduct its electrical signal. A high level slows the heart and can stop it; a low level causes weakness, and in cats a distinctive drooping of the head and neck. Either extreme is treated as urgent.
What a high result can mean
- A urinary obstruction — a blocked male cat is the classic and life-threatening example
- Acute kidney injury, or a ruptured bladder
- Hypoadrenocorticism (Addison's disease) in dogs, with low sodium alongside
- Haemolysis of the sample in some breeds, notably Akitas and Shiba Inus, whose red cells are rich in potassium
- Severe tissue damage, or a sample that sat too long before being separated
What a low result can mean
- Chronic kidney disease in cats — a common and treatable finding
- Vomiting, diarrhoea, or a prolonged period of not eating
- Diuretic treatment
- Insulin treatment, which drives potassium into cells
- Hyperaldosteronism, an uncommon adrenal condition seen in older cats
Dogs and cats differ
Low potassium is a routine part of managing chronic kidney disease in cats, and supplementing it often produces a visible improvement in strength and appetite. High potassium from urinary obstruction is overwhelmingly a male cat problem — a cat straining in the litter tray and producing nothing needs to be seen immediately, not the next morning.
Questions worth asking your vet
- Is my cat straining to urinate — does this need seeing right now?
- Would potassium supplementation help my cat's kidney disease?
- Could the sample handling have raised this artificially?
Related terms
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