Urea

You should get a blood urea test if you have swelling in the feet or face, reduced or foamy urine, fatigue, nausea, vomiting, confusion, or signs of dehydration. It is also recommended for people with diabetes, high blood pressure, heart failure, or kidney disease, during routine check-ups, and when taking medicines that affect the kidneys.

Fasting for 8–12 hours is often recommended before a blood urea test, and you may drink water during this time. Avoid heavy meat or high-protein meals, alcohol, and strenuous exercise for 24 hours beforehand, as these can raise urea levels. Stay well hydrated, and inform your doctor about medicines like steroids, diuretics, or antibiotics.

Fasting is often recommended for a blood urea test. You may be asked to fast for 8–12 hours, drinking only water. More importantly, avoid heavy meat or high-protein meals and strenuous exercise for 24 hours beforehand, as they can temporarily raise urea levels. Follow your doctor's or lab's specific instructions.