Comparison of serum total calcium, albumin-corrected total calcium, and ionized calcium in 1213 patients with suspected calcium disorders

Effect of induced hypocalcemia in nonlactating, nonpregnant Holstein cows fed negative DCAD with low, medium, or high concentrations of calcium

“…Calcium status as determined by tCa is based on the assumption that tCa and iCa are proportional and that the proportional relationship is static. Previous research in both humans and dogs have demonstrated that both tCa concentrations and tCa concentrations that have been adjusted for variables such as serum albumin are unacceptable for predicting iCa status (Thode et al, 1989;Schenck and Chew, 2005). This is 1 possible explanation for why we were unable to detect treatment differences in tCa concentrations in this experiment.…”

Dysregulated Mineral Metabolism in AKI

“…56,57 Furthermore, albumin-corrected total serum calcium equations have been shown to be unreliable in other clinical settings, such as critical illness, 58,59 CKD, 60 end-stage renal disease, 61 and among patients suspected of having calcium metabolic disease. 62 Thus, we recommend iCa as the preferred method for assessment of calcium levels in patients with AKI.…”

Ionized Calcium Measurement in Serum and Plasma by Ion Selective Electrodes: Comparison of Measured and Calculated Parameters

“…Forty five to fifty percent of the total calcium (CaT) in plasma is iCa, which is the free and biologically active form [3,4], 40 % is protein bound and the remaining 10-15 % is Ca complexed to anions like phosphates, sulphates, lactate and citrate [5,6]. Redistribution of Ca among the three plasma pools can occur acutely or chronically, by changes in the concentration of protein, small anions or alteration in pH [7][8][9]. iCa is kept in the narrow reference range of 1.15-1.33 mmol/L by an integrated homeostatic mechanism involving parathyroid hormone and 1, 25 dihydroxy vitamin D axis.…”