Elevation of serum calcium concentration and changes in other blood parameters after death

Abstract

A postmortem rise in serum total and ultra-filterable calcium concentrations was observed in man and in the rat, the changes occurring more rapidly at room temperature than at 4°C. The mechanism responsible for this rise was investigated in the rat by measuring the concentrations of magnesium, sodium, potassium, chloride, and nitrogen in serum, whole blood, and skeletal muscle. Among the changes observed were an increase in total nitrogen concentration in serum and whole blood, a decrease in total nitrogen concentration in muscle, an increase in red cell volume, and a decrease in the extracellular fluid volume, as measured by inulin. It is concluded that postmortem hypercalcemia is due mainly, to hemoconcentration resulting from failure of the “sodium pump,” movement of sodium and chloride ions into cells, a temporary rise in osmotic pressure within the cells, and consequent movement of water from the extracellular fluid compartment into cells.