BUN

You should get a BUN test if you have swelling in the feet or face, reduced or foamy urine, fatigue, nausea, 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 BUN 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 BUN levels. Stay well hydrated, and inform your doctor about medicines like steroids, diuretics, or antibiotics.

Fasting is often recommended for a BUN 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 BUN levels. Follow your doctor's or lab's specific instructions.