Table 4.

Area under the ROC curves and their 95% confidence interval of predicted ionized calcium, total calcium, and 2 corrected total calcium formulas for diagnosis of hypocalcemia and hypercalcemia in dogs of the test set

	Hypocalcemia*		Hypercalcemia
	AUC	95% confidence interval	AUC	95% confidence interval
piCa	0.80	0.74–0.85	0.95	0.88–1.00
tCa	0.67	0.61–0.74	0.89	0.81–0.96
Corrected tCa1	0.70	0.64–0.77	0.92	0.84–0.99
Corrected tCa2	0.68	0.62–0.75	0.90	0.83–0.97

Hypocalcemia is defined as measured ionized calcium <1.11 mmol/L, and hypercalcemia is defined as measured ionized calcium >1.37 mmol/L. For hypocalcemia, there was a significant difference for the areas under the curve among the 4 techniques (*P < 0.001). piCa, predicted ionized calcium; tCa, total calcium; Corrected tCa1, total calcium corrected with albumin; Corrected tCa2, total calcium corrected with total protein; AUC, area under the curve.