Normal Range of Urea

Urea is the primary end-product of human protein metabolism. The general normal reference range is typically 1.8–9.5 mmol/L, though specific values may vary depending on age and sex.

Urea levels reflect both renal function and protein metabolism status. The overall normal reference range is 1.8–9.5 mmol/L; however, more specific ranges include: • Men aged 20–59 years: 3.1–8.0 mmol/L • Women aged 20–59 years: 2.6–7.5 mmol/L • Men aged 60–79 years: 3.6–9.5 mmol/L • Women aged 60–79 years: 3.1–8.8 mmol/L • Infants and children: 1.8–6.5 mmol/L A urea level below the normal range may result from inadequate dietary protein intake or pregnancy, among other causes.

Elevated urea levels may arise from multiple factors. For example, high-protein diets increase urea production. When renal function is impaired—as in conditions such as glomerulonephritis or renal arteriosclerosis—the kidneys’ ability to excrete urea declines, leading to its accumulation in the bloodstream and consequently elevated serum urea concentrations. Thus, serum urea serves as an important indicator for evaluating renal function and nutritional status. Clinicians typically interpret abnormal urea values in conjunction with the patient’s medical history, clinical symptoms, and results of other diagnostic tests to determine the underlying cause.

Maintain healthy lifestyle habits in daily life: avoid excessive fatigue and strenuous physical activity, which may provoke discomfort. Instead, engage in moderate exercise appropriate to your individual health status—such as walking or slow jogging—to enhance immune resistance and support recovery.