Which lab measurement reflects functional or long-term selenium status?

Which lab measurement reflects functional or long-term selenium status?

• A. Plasma glutathione peroxidase
• B. Plasma selenium level
• C. Erythrocyte selenium concentration
• D. Methionine level

Answer: (A)

Functional selenium status is best assessed by the activity of selenoproteins, such as glutathione peroxidase. Selenium must be incorporated into these enzymes to become active, so measuring glutathione peroxidase activity shows whether the body is actually using selenium to make functional enzymes. This makes plasma glutathione peroxidase a direct readout of how well selenium is supporting antioxidant defense, reflecting functional status and, over time, adequacy. Plasma selenium level indicates recent intake or circulating stores but not how effectively those stores are being used; erythrocyte selenium concentration lies more with long-term stores and does not directly measure enzyme function; methionine level isn’t a direct marker of selenium status.

Functional selenium status is best assessed by the activity of selenoproteins, such as glutathione peroxidase. Selenium must be incorporated into these enzymes to become active, so measuring glutathione peroxidase activity shows whether the body is actually using selenium to make functional enzymes. This makes plasma glutathione peroxidase a direct readout of how well selenium is supporting antioxidant defense, reflecting functional status and, over time, adequacy. Plasma selenium level indicates recent intake or circulating stores but not how effectively those stores are being used; erythrocyte selenium concentration lies more with long-term stores and does not directly measure enzyme function; methionine level isn’t a direct marker of selenium status.