Diagnostic performance of predicted ionized calcium in dogs with total hypercalcemia and total hypocalcemia.

Evaluating tCa alone does not reliably determine ionized calcium status. Even with hyperphosphatemia, piCa and its PI represent a reliable alternative to interpret abnormal tCa values when ionized calcium measurements are not available. However, if the tCa reference interval is notably different from 7.6 to 11.4 mg/dL, piCa values might be under/overestimated.