Which statement about selenium status testing is true?

Which statement about selenium status testing is true?

• A. Plasma glutathione peroxidase is not related to selenium status
• B. Selenium level in saliva is a standard measure
• C. Erythrocyte selenium concentration is a valid measure
• D. Urinary selenium excretion is the sole measure of status

Answer: (C)

Assessing selenium status is most reliable when looking at a measure that reflects body stores over time rather than just recent intake. Erythrocyte selenium concentration is a valid measure because red blood cells incorporate selenium into selenoproteins during their formation and remain in circulation for about 120 days. This gives an integrated picture of selenium status over several months, making it a stable and informative indicator of body stores. While plasma glutathione peroxidase is a selenium-dependent enzyme and its activity does relate to selenium status, relying on this functional marker alone can be less reliable because enzyme activity can be influenced by other factors and doesn't quantify total selenium stores. Saliva selenium is not a standard measure, and urinary selenium excretion reflects recent intake more than long-term stores, so it’s not used as the sole indicator of status.

Assessing selenium status is most reliable when looking at a measure that reflects body stores over time rather than just recent intake. Erythrocyte selenium concentration is a valid measure because red blood cells incorporate selenium into selenoproteins during their formation and remain in circulation for about 120 days. This gives an integrated picture of selenium status over several months, making it a stable and informative indicator of body stores.

While plasma glutathione peroxidase is a selenium-dependent enzyme and its activity does relate to selenium status, relying on this functional marker alone can be less reliable because enzyme activity can be influenced by other factors and doesn't quantify total selenium stores. Saliva selenium is not a standard measure, and urinary selenium excretion reflects recent intake more than long-term stores, so it’s not used as the sole indicator of status.