What level of Random Blood Sugar in an adult should raise suspicion of Diabetes Mellitus?

Raj. CHO -2020

Medical & Surgical Nursing

Easy

Appeared in: Raj. CHO -2020

Explanation

A random blood sugar (RBS) level of 200 mg/dL or higher is a critical threshold that strongly suggests a diagnosis of Diabetes Mellitus.
This finding, especially when accompanied by classic symptoms of hyperglycemia (such as increased thirst, frequent urination, and unexplained weight loss), is considered diagnostic.
According to American Diabetes Association (ADA) and WHO guidelines, a single random plasma glucose value at or above this level warrants a diagnosis, often without needing immediate confirmatory tests if symptoms are present.

Option A: This range (80-100 mg/dL) represents a normal fasting blood glucose level and does not indicate hyperglycemia or diabetes.
Option B: This range (100-140 mg/dL) is not the specific diagnostic threshold for diabetes on a random test. While a fasting value of 100-125 mg/dL indicates prediabetes, a random value in this range is not sufficient for a diagnosis.
Option C: While a value above 140 mg/dL is abnormal, 200 mg/dL is the specific cut-off for a diabetes diagnosis on a random test. The range of 140-199 mg/dL is used to define impaired glucose tolerance (prediabetes) in a 2-hour oral glucose tolerance test (OGTT), not a random test.

Visual 1: Chart: A comparative chart illustrating the diagnostic cut-off values for Diabetes Mellitus, Prediabetes, and Normal ranges for Fasting Plasma Glucose, 2-hour Oral Glucose Tolerance Test (OGTT), Random Blood Sugar, and HbA1c. This helps visualize the different testing methods and their corresponding values.

Clinical Relevance

Nursing practice connection: Knowing Diagnostic criteria for Diabetes Mellitus using Random Blood Sugar (RBS) helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
A nurse encountering a patient with an RBS of 200 mg/dL or more must recognize this as a critical value, assess for symptoms of hyperglycemia (polyuria, polydipsia, polyphagia), and ensure prompt physician notification for further evaluation and management.
Patient education is crucial. The nurse should be prepared to explain the significance of the high reading and the need for follow-up testing in simple terms, without causing undue alarm.
What if? If the patient's RBS was 180 mg/dL and they were asymptomatic, the nurse's action would change. This value falls into a grey area. While not diagnostic for diabetes, it is elevated. The nurse should document the finding, inform the physician, and anticipate orders for more definitive tests like a Fasting Plasma Glucose or HbA1c to clarify the patient's glycemic status.

How to Approach the Question

First, identify the core of the question, which is asking for a specific laboratory value used for diagnosis. The keywords are 'Random Blood Sugar' and 'Diabetes Mellitus'.
Second, recall the standard diagnostic criteria for diabetes. It's important to differentiate between the values for fasting, post-prandial (after a meal), and random glucose tests.
Third, evaluate the given options against the known diagnostic thresholds. Eliminate options that represent normal or prediabetic ranges for other types of tests.
Option A (80-100 mg/dl) is the normal fasting range. Option B (100-140 mg/dl) can be normal post-meal or indicate prediabetes if fasting. Option C (>140 mg/dl) is the threshold for impaired glucose tolerance in an OGTT, not the random diagnostic value.
Finally, select the option that matches the established diagnostic criterion for a random blood sugar test, which is a value of 200 mg/dL or greater.

Concept Tested & Keywords

Concept Tested: Diagnostic criteria for Diabetes Mellitus using Random Blood Sugar (RBS).
Stem keywords: Random Blood Sugar, adult, Diabetes Mellitus, suspicion
Lead-in keywords: What level

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