Urea is a waste product that is formed through the breakdown of proteins and electrolytes are dissolved salts, like sodium, potassium, chloride and bicarbonate; both are found in trace amounts in urine, as reported by Prevention. High levels of urea detected in the urine can be an indication that the body is either dehydrated or that the kidneys are malfunctioning while low levels of urea may be a sign of pregnancy, starvation or the presence of chronic liver diseases. High levels of electrolytes are typically an indication of underlying kidney problems while low levels can also be an indication of underlying medical problems, like liver failure and Addison's disease.
Generally speaking, when testing for electrolyte levels, medical experts gauge a sodium concentration of less than 120 mmol per liter as an indication of hyponatraemia. Patients with hyponatraemia will need to provide both a urine sample and blood work in order for medical experts to better determine what the underlying cause may be. Hyponatraemia can be a result of drug therapy, and the patient's medical history will also be taken into consideration during the diagnosis.
Potassium levels are also measured when looking into electrolyte levels. Hypokalaemia is characterized as potassium levels below 3.5 mmol per liter whereas hyperkalaemia is characterized as potassium levels above 5.5 mmol per liter.