The calcium fractions in the plasma of patients on dialysis

Plasma calcium difference between man and vertebrates

1. Literature data about the plasma content of total calcium, ionized calcium and inorganic phosphate in healthy animals and man of different age and sex were collected. 2. It was established that under normal conditions ionized calcium is about 45% of total calcium. 3. The degree of saturation of these blood samples with respect to octocalcium phosphate OCP was calculated. 4. In young animals and man the blood plasma has a higher degree of saturation than in adult animals and man. 5. The blood plasma of healthy animals is supersaturated with respect to OCP during their whole life. 6. However, the blood plasma of healthy human adults is slightly undersaturated with respect to OCP.

Ionized calcium in body fluids

This article will review the methods currently available to the clinician and research worker for measuring the concentration of ionized calcium in various body fluids including whole blood, serum, plasma, urine, cerebrospinal fluid, milk, and synovial fluid. The methods to be reviewed are based on procedures involving bioluminescence, colorimetry and ion-selective electrodes. Emphasis will be given to the precision and, wherever possible, accuracy of each technique. Possible sources of error and interfering agents will be identified. Attention will be given to the recommended conditions for measuring ionized calcium in each body fluid. An assessment will be made of the theoretical and practical importance of measuring ionized calcium rather than total calcium and of its value in clinical medicine.