Glucose decreases per hour under room temperature conditions?

• A. 2 mg/dL
• B. 4 mg/dL
• C. 7 mg/dL
• D. 10 mg/dL

Answer: (C)

Glucose in whole blood decreases at room temperature because red and white blood cells keep metabolizing glucose (glycolysis) after the sample is drawn. The rate most commonly cited for unprocessed blood at room temperature is about 7 mg/dL per hour. So, the expected drop per hour under these conditions is approximately 7 mg/dL, making that value the best match. This is why prompt processing, placing samples on ice, or using glycolysis inhibitors (like fluoride-oxalate tubes) is recommended to prevent underestimation of glucose. The smaller figures would understate the typical glycolytic loss, while the higher figure is less commonly observed in routine practice, though it can occur under certain conditions.