Adjusted Calcium Is Lying — And Labs Keep Printing It

Choy et al. argue it's time to stop trusting a number that's been unreliable for fifty years.

By
Kerri Miller
March 18, 2026
1 min

MDSpire News

Objective:

To highlight the limitations of albumin-adjusted calcium and advocate for the use of ionised calcium, emphasizing its clinical advantages.

Approach:

Key Findings:

Albumin-adjusted calcium is unreliable in elderly, critically ill, and renally impaired patients.
pH and protein disturbances can undermine correction formulas for adjusted calcium.
Universal reporting of albumin-adjusted calcium can lead to misdiagnosis of hypo- or hypercalcaemia.
The concept of 'corrected calcium' has been challenged since the 1970s, with evidence accumulating against its use.

Interpretation:

Accumulating evidence suggests that ionised calcium should replace albumin-adjusted calcium in clinical practice due to its reliability in various patient populations.

Limitations:

Continued use of albumin-adjusted calcium despite known limitations can lead to misdiagnosis and inappropriate treatment.
Potential for misdiagnosis due to reliance on outdated correction formulas, impacting patient outcomes.

Conclusion:

Clinicians should be aware of the limitations of albumin-adjusted calcium and consider ionised calcium as a preferred alternative, implementing this change in practice.