Urea is the end product of protein breakdown, made in the liver from ammonia and excreted by the kidneys. The blood level reflects both how much protein is being broken down and how well the kidneys are clearing it. Reported in some laboratories as blood urea nitrogen, it speaks for kidney function and protein turnover together.
No readings for this marker yet.
Raised urea most often accompanies dehydration, a high protein intake, bleeding into the gut, or reduced kidney filtration; a rise that outpaces creatinine typically suggests a pre-renal cause such as fluid loss. Lowered urea is most often seen with a low protein diet, pregnancy, overhydration, or significant liver disease, since the liver makes it. Direction matters more than a single figure, and any persistent change belongs in a conversation with a doctor.
Meals rich in protein, fasting, fluid status, and recent gastrointestinal bleeding move the result noticeably, which makes urea a less stable marker than creatinine on its own. Certain drugs, including corticosteroids and diuretics, also raise it. It is interpreted next to creatinine and eGFR, with their ratio carrying much of the meaning, and cystatin C adds a filtration estimate independent of muscle mass.
Reference ranges are general adult values and depend on lab, assay, age and sex. For orientation, not diagnosis — discuss results with your doctor.