Related Experiment Videos
Updated total calcium reference intervals for Abbott Alinity c using Calcium2 reagents
Yasser Tabana1, Vathany Kulasingam2, Tobias Fischer3
1Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada.
Background:
A new formulation of total calcium reagents (Calcium2) for the Abbott Alinity c prompted re-evaluation of reference intervals (RI). Despite ongoing standardization efforts, differences in reagents and analytical platforms can introduce systematic bias.
Methods:
Direct and indirect approaches were used to evaluate calcium RI for both a legacy formulation of calcium (CaOLD) and the new calcium2 reagents (CaNEW) on the Abbott Alinity c. The indirect method involved a large real-world dataset comprising 97,452 CaOLD results and 106,728 CaNEW results obtained from the University Health Network. Standardized preprocessing included consideration for risk wards, exclusion of patients with more than one result, abnormal albumin levels, and individuals outside of 18-110 years of age. Indirect methods employed include refineR, TML, and RefLim. The direct method by non-parametric estimation involved 173 subjects with normal ionized calcium and albumin levels. RI were subsequently verified using an additional 34 healthy volunteers.
Results:
Across indirect methods, similar RI were obtained when only patients with a single result, and exclusion of risk wards and abnormal albumin were considered. The approach by refineR provided 2.10-2.48 mmol/L (CaNEW) vs. 2.16-2.55 mmol/L (CaOLD), whereas the RefLim method provided 2.10-2.47 mmol/L (CaNEW) vs. 2.15-2.54 (CaOLD) and TML provided 2.11-2.48 mmol/L (CaNEW) vs. 2.17-2.55 mmol/L (CaOLD). The non-parametric method produced RI of 2.05-2.50 mmol/L(CaNEW) and 2.06-2.52 mmol/L (CaOLD).
Conclusion:
The RI for total calcium on the Abbott Alinity c with CaNEW is lower than previously established.