Albumin adjusted calcium: Study in a tertiary care hospital
- Author:
Zaki Anuar Mohd Ariffin
1
Author Information
1. Department of Pathology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur Malaysia
- Collective Name:Farhi Ain Jamaluddin
- Publication Type:Journal Article
- Keywords:
Total calcium;
serum albumin;
corrected calcium;
albumin-adjusted calcium equation
- From:The Malaysian Journal of Pathology
2020;42(3):395-400
- CountryMalaysia
- Language:English
-
Abstract:
Introduction: One commonly used equation which continues to be widely mentioned in text books and
hence familiar to clinical people is total calcium + 0.02 (40 – albumin). This equation was derived
using cresophthalein complexone and bromocresol green (BCG) methods for measuring serum total
calcium and serum albumin respectively. However this equation maybe invalid when applied to calcium
and albumin results generated by alternative assays. Hence we aim to derive an albumin-adjusted
calcium equation specific to our laboratory’s total calcium and albumin methodologies. Materials
and Methods: A total of 3,175 adult University Malaya Medical Centre (UMMC) patients deemed
free of any calcium metabolism disorders were selected and divided into two groups for derivation
and validation. Simple linear regression associating total calcium and albumin was constructed from
the data in the derivation group. The new albumin-adjusted calcium equation was validated in the
validation group. Differences in calcium status classification following adjustments based on existing
and new albumin-adjusted calcium equation was compared in a 469 hypoalbuminaemic patients.
Result: The new albumin adjusted calcium equation was: total calcium + 0.014 x (39-albumin). Of
the 469 hypoalbuminemic patients, 78 were classified differently based on new equation. Based on
the new equation, 55 normocalcemic patients were classified as hypocalcemic and 22 were classified
as normocalcemic instead of hyperclacaemic. Conclusion: Based on the newly derived albuminadjusted calcium equation 17% of patients had different adjusted calcium classifications. This could
potentially impact in the management. It is recommended that laboratories derive equations specific
to their calcium/albumin methods and analytical platforms.
- Full text:5.2020my01086.pdf
