Magnesium (Mg)
Electrolytes & minerals ·Also called: Mg, magnesium, serum magnesium
What it is
Most magnesium is inside cells and in bone, with only a small fraction in blood. Like calcium it circulates in bound and free forms, and the free fraction is the physiologically active one.
Why your vet measures it
Low magnesium is common in hospitalised animals and easy to overlook. It blocks the correction of low potassium and low calcium, so a patient whose potassium keeps drifting down despite supplementation often turns out to be magnesium-depleted.
What a high result can mean
- Reduced kidney function, which is the main route of excretion
- Over-supplementation, or magnesium-containing medications
What a low result can mean
- Critical illness, particularly diabetic ketoacidosis
- Prolonged loss of fluid through vomiting or diarrhoea
- Diuretic treatment
- Poor intake over a long period
Questions worth asking your vet
- If my pet's potassium is not correcting, has magnesium been checked?
- Does this need supplementing while my pet is on fluids?
Related terms
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