A sample drawn for which of the following requires special timing due to diurnal variation in its blood levels?

Question

Quizplus · Accepted Answer

Cortisol levels in the blood follow a diurnal variation, peaking in the morning and decreasing throughout the day. Therefore, to accurately measure cortisol levels, a sample needs to be drawn at a specific time of day, usually in the morning. Hemoglobin, potassium, and sodium levels do not show diurnal variation, and their levels remain fairly consistent throughout the day.

A Sample Drawn for Which of the Following Requires Special