Assessment of calcaemic status in geriatric hospital patients: Serum ionized calcium versus albumin-adjusted total calcium

Abstract

To evaluate the accuracy of total serum calcium (CaT) and albumin-adjusted total calcium (CaA) determinations in the assessment of calcaemic status in the elderly, serum ionized calcium (CaI), CaT and serum albumin (Alb) concentrations were measured in 558 geriatric hospital patients. As expected, CaT was correlated with Alb (r=0.316, p<0.001) and Cal with serum pH (r=−0.351, p<0.001) and they were closely interrelated (r=0.746, p<0.001). Various albumin-adjustment formulas from the literature decreased the correlation of CaT and Cal. Using conventional reference limits for CaT only 12% and 72% of patients with Cal above or below the reference limits for CaI, respectively, were found.

This study demonstrates the low sensitivity of total and albumin-adjusted calcium in the detection of slightly or moderately abnormal calcaemic states.

Key Words:

• ageing
• albumin
• serum calcium