AMT Practice Exam 2025 – Complete Test Preparation

Capillary blood is known to reflect the physiological conditions occurring in tissues more closely than venous blood. One of the key substances that can be found in higher concentrations in capillary blood compared to venous blood is glucose. This is largely due to the fact that glucose is actively delivered to tissues and is used as a primary energy source by cells during metabolic processes.

In contrast, while urea, cortisol, and calcium are all important substances in the body, their concentrations tend to be more stable and consistent across different blood vessels. Urea reflects metabolic waste produced by protein breakdown and is typically excreted by the kidneys, maintaining similar levels in both capillary and venous blood. Cortisol, being a steroid hormone, has a more regulated release and does not show significant differences between these blood types, largely due to its systemic nature and role in stress response. Calcium levels can also fluctuate based on various physiological processes but are generally maintained at similar levels in both venous and capillary blood.

Thus, glucose stands out as a substance that shows a significant differential concentration in capillary blood when compared to venous blood, particularly after meals when it's quickly delivered to the tissues.