ionized calcium in AKI patients

Q: What are the two reasons to prefer serum ionized calcium measurement over total serum calcium level in Acute Kidney Injury (AKI) patients?



Answer: One well-known reason to measure serum ionized calcium in AKI patients is the fact that the total serum calcium concentration does not accurately reflect the actual calcium level as these patients may have low serum albumin levels, and calcium is bound to albumin. 

The objective of above question is to highlight the second reason to prefer serum ionized calcium measurement over total serum calcium measurement in AKI patients. The binding of calcium to albumin is pH dependent, and the amount of free calcium may be altered by acid-base disorders or by its rapid correction.

#nephrology
#acidbase
#electrolytes