Daily Variation in the Concentration of Iron in Serum

Abstract
Measurements of concentration of serum Fe were made at the Mayo Clinic in 11 normal persons to determine whether there was a time at which the day-to-day values showed the least fluctuation. Values for serum Fe in the same person showed wide variation at the same time on different days. Observations were made on 1 person during a 3-day fast; the values for serum Fe fluctuated during such deprivation of food. The total serum Fe-binding capacity was not involved in this diurnal variation.