Whenever someone falls ill, like say having diarrhoea or high fever, changes take place in our blood due to loss of fluids; this is called dehydration.
Dehydration can cause loss of some essential minerals like sodium, potassium, calcium, phosphates, or magnesium. How do we know that we have lost these minerals? Well, your doctor will simply Serum Electrolytes order a blood test called Serum Electrolytes and you know which minerals you are lacking in.
So, you know that you are deficient in some minerals- what's next? Next, your doctor may either suggest hospitalization [if the electrolyte loss is severe] or administer you with fluids that contain these electrolytes that will take care of this loss and make you bounce to your feet once again.