A patient passes urine as given in the sequence: Tuesday 8 AM 200 ml, 12 noon 250 ml, 3 PM 300 ml, 6 PM 300 ml, 9 PM 250 ml, Wednesday 3 AM 200 ml, 8 AM 300 ml. The 24 hour 8 AM to 8 AM collection of urine for laboratory evaluation is quantified to be:

Appeared in: GMCH - 2016

Explanation

The standard procedure for a 24-hour urine collection requires discarding the first voided specimen at the start of the collection period.
All urine produced during the 24-hour window after the initial discarded sample is collected.
The collection concludes with a final voiding at the end of the 24-hour period, which is added to the total volume.
Following this procedure, the total volume is calculated by summing all collected samples: 250 + 300 + 300 + 250 + 200 + 300 = 1600 ml.

Option A: This value is an incorrect summation and does not correspond to any logical misapplication of the collection rules.
Option B: This value (1500 ml) is obtained by incorrectly including the first discarded sample (200 ml) and excluding the final required sample (300 ml). The correct procedure is the opposite.
Option D: This value (1800 ml) is the sum of all listed urine outputs, including the first sample that should have been discarded. This is a common error in calculation.

Clinical Relevance

Nursing practice connection: Use the key finding related to Procedure and Calculation for 24-Hour Urine Collection to guide bedside assessment, documentation, and the next nursing action.
Accurate 24-hour urine collection is crucial for diagnosing and monitoring various conditions, including kidney disease (e.g., measuring creatinine clearance), hormonal imbalances (e.g., cortisol levels for Cushing's syndrome), and metabolic disorders.
Nurses play a vital role in patient education, ensuring the patient understands the importance of collecting every sample (except the first) and storing it correctly to prevent inaccurate test results, which could lead to misdiagnosis or improper treatment.
What if the patient forgets to collect one sample in the middle of the 24-hour period? The entire collection is considered invalid. The nurse must document the missed sample and notify the healthcare provider. The test will need to be rescheduled and restarted from the beginning to ensure accuracy.

How to Approach the Question

First, identify the question type. This is an analytical question requiring calculation based on a specific clinical procedure.
Identify the start and end times of the collection period (Tuesday 8 AM to Wednesday 8 AM).
Recall the key principle of a 24-hour urine collection: discard the first void, collect all subsequent voids, and include the final void at the end time.
Apply this principle to the given data: ignore the 200 ml from Tuesday 8 AM.
Sum all the remaining volumes, including the final 300 ml from Wednesday 8 AM.
Compare your calculated total with the given options to find the correct answer.

Concept Tested & Keywords

Concept Tested: Procedure and Calculation for 24-Hour Urine Collection
Stem keywords: 24 hour urine collection, urine output, laboratory evaluation, quantified
Lead-in keywords: quantified to be
Clinical cues: Collection period from 8 AM to 8 AM

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E6 Nursing Fundamentals Potter Perry 12e Part 5 p. 245-247

E6 textbook of Applied Biochemistry and Nutrition & DieteticsHarbans Lal (pp 26-464 of 479) p. 224-226

E6 Pathology-Vandana Puri & Kavita Gaur Textbook of Pathology and Genetics p. 444-446

Practise the full GMCH - 2016

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