Stress increases urinary urea nitrogen, by reducing net protein utilization and increasing obligatory nitrogen excretion. Thus urinary nitrogen can be used to assess patients for catabolic stress.


stress index =

= (24 hour urinary urea nitrogen in grams) - ((0.5 * (24 hour nitrogen intake in grams) + 3)



• 3 indicates the obligatory urine urea nitrogen excretion in grams per day



• A stress index < 1 indicates no significant catabolic stress.

• A stress index between 1-5 indicates moderate catabolic stress.

• A stress index > 5 indicates severe catabolic stress.


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