In an Adult, Anuria is defined as a urine output less than what amount?

Appeared in: MP CHO-2020

Explanation

Anuria is clinically defined as a urine output of less than 100 mL per day in an adult.
This extremely low volume indicates that the kidneys are either not producing urine or that the urine produced cannot exit the body.
It represents a more severe condition than oliguria, which is defined as a urine output of less than 400 mL per day.
Anuria is a critical sign of severe renal dysfunction or complete urinary tract obstruction and constitutes a medical emergency.

Option A: While a urine output of 50 mL/day falls within the definition of anuria, the established clinical threshold is less than 100 mL/day. Some sources may refer to less than 50 mL/day as 'complete anuria,' but 100 mL is the standard upper limit for the definition.
Option C: A urine output of 150 mL per day is incorrect. This value falls into the category of oliguria (less than 400 mL/day), not anuria.
Option D: A urine output of 200 mL per day is incorrect. This value is classified as oliguria, which is a precursor or less severe form of renal impairment compared to anuria.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Definition of Anuria and Urine Output Assessment as background academic context rather than a clinical decision trigger.
Accurate measurement and documentation of urine output are fundamental nursing responsibilities for assessing fluid balance and kidney function.
Anuria is a 'red flag' sign. Its identification must trigger prompt nursing actions, including assessment for obstruction and immediate notification of the medical team.
What if? If a patient with a Foley catheter suddenly becomes anuric, the nurse's first action is to check the catheter and tubing for kinks or obstruction. This simple mechanical check can often resolve the issue and must be done before assuming a physiological cause.

How to Approach the Question

First, identify the key term in the question, which is 'Anuria'.
This is a factual recall question that requires knowledge of standard medical and nursing terminology.
Recall the specific definitions for different levels of urine output: normal, polyuria, oliguria, and anuria.
Remember that anuria represents the most severe reduction in urine output.
Compare the standard definition of anuria (less than 100 mL/day) with the options provided.
Select the option that correctly states this clinical threshold.

Concept Tested & Keywords

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E6 Medicine Davidson Principles Practice 24e p. 411-413

Practise the full MP CHO-2020

Attempt every question from this paper in a timed mock, then review the full solution for each one.