Questioning Medicine

Desgagnés N et al. Use of albumin-adjusted calcium measurements in clinical practice. JAMA Netw Open 2025 Jan 21; 8:e2455251. (https://doi.org/10.1001/jamanetworkopen.2024.55251)Overall, total calcium levels (just the ones we would get back on a basic cmp) correlated better with ionized calcium than did formula-corrected calcium levels. Formulas with stronger correlation than total calcium levels were either complex (e.g., requiring blood pH measurement) or derived locally (i.e., not generalizable). Many formulas overestimated calcium at low calcium levels; the Payne formula misclassified 41% of patients, whereas the total calcium level only misclassified 25% of patients.