Lian IA, et al. - Using regression coefficients of albumin researchers constructed local adjustment formulas and examined if the diagnostic accuracy was improved compared with previously published formulas and unadjusted calcium to evaluate hypocalcaemia or hypercalcaemia in patients above 2 years of age. During this study, free calcium standardised at pH 7.40, total calcium, creatinine, albumin and phosphate had been analysed in a single blood draw, including hospitalised patients and patients from outpatient clinics and general practice. Data displayed the superiority of the diagnostic accuracy of unadjusted total calcium to several commonly used adjustment formulas. The use of such formulas ought to be abandoned in clinical practice. If the clinician did not trust total calcium to depict the calcium status of the patient, estimation of free calcium was recommended.

Methods

• The plot of this research was a retrospective hospital laboratory data study.
• Data was extracted from the local hospital laboratory data system.
• It was performed in Norway, 2006-2015.
• Eligible candidates comprised of 6,549 patients above 2 years of age, where free calcium standardised at pH 7.40, total calcium, creatinine, albumin and phosphate had been analyzed in a single blood draw, including hospitalised patients and patients from outpatient clinics and general practice.
• Diagnostic accuracy by Harrell’s c and receiver operating characteristic curve analysis, using free calcium standardised at pH 7.40 as a gold standard, in subgroups with estimated glomerular filtration rate (eGFR) ≥60 or <60 mL/min/1.73 m² served as the primary outcome.

Results

• The Harrell’s c of unadjusted total calcium (0.801) was discovered to be considerably larger compared to those of the local formulas (0.790, p=0.002) and the best formula taken from literature (0.791, p=0.004), among the subgroup with eGFR <60 mL/min/1.73 m².
• As per the results, There were no major variations between these 3 formulas in the subgroup with eGFR ≥60 mL/min/1.73 m².