What is the renal threshold value of glucose?

Appeared in: RRB Nsg. Superintendent 21 July 2019 (shift 1st)

Explanation

The renal threshold for glucose is the plasma concentration above which glucose spills into the urine.
In a healthy individual, the renal tubules can reabsorb all filtered glucose as long as the plasma level is below a certain point.
The standard, widely accepted value for this threshold is 180 mg/dL.
Above this level, the transport mechanisms for glucose in the proximal tubule become saturated, leading to glycosuria (glucose in the urine).

Option A: This value is slightly higher than the standard accepted renal threshold for glucose.
Option B: This value is significantly higher than the standard renal threshold for glucose.
Option C: This value is slightly higher than the standard accepted renal threshold for glucose.

Visual 1: Diagram - A diagram of the nephron illustrating the process of glomerular filtration and tubular reabsorption of glucose. This helps visualize where the threshold mechanism occurs.
Visual 2: Graph - A graph plotting plasma glucose concentration against the rate of glucose excretion. It should show zero excretion until the 180 mg/dL threshold is reached, after which excretion increases linearly.

Clinical Relevance

Nursing practice connection: Knowing Renal threshold for glucose helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
Understanding the renal threshold is crucial for nurses when interpreting urinalysis results. The presence of glucose in urine (glycosuria) is a key indicator of hyperglycemia, most commonly associated with diabetes mellitus.
It is important to know that glycosuria is not always indicative of diabetes. Conditions like renal glycosuria or pregnancy can lead to glucose in the urine with normal blood sugar levels.
A nurse must correlate urine findings with blood glucose measurements for an accurate assessment.

How to Approach the Question

This is a factual recall question that tests your knowledge of basic renal physiology.
Identify the key term in the question: 'renal threshold value of glucose'.
Recall the standard physiological value for this threshold from your studies.
Compare the recalled value with the given options.
Select the option that matches the standard value, which is 180 mg/dL.

Concept Tested & Keywords

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Practise the full RRB Nsg. Superintendent 21 July 2019 (shift 1st)

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