Assessment and clinical course of hypocalcemia in critical illness

Table 3 The performance of locally validated and published formulas for adjusted calcium in predicting hypocalcemia.

Formula		Sens (%)	Spec (%)	PPV	NPV	AUC (95% CI)
Locally Validated	AdjCa=Total Ca+0.013(44.1-Alb)	78.2	63.3	72.4	70.2	0.78 (0.75-0.81)
Traditionally quoted [24]	AdjCa=Total Ca+0.02(40-Alb)	60.4	69.0	70.6	58.7	0.71 (0.68-0.74)
Slomp et al. [24]	AdjCa=Total Ca+0.025(40-Alb)	32.3	78.9	65.4	48.6	0.64 (0.61-0.68)
Slomp et al. [24]	AdjCa=Total Ca+0.00839(32.9-Alb)	97.4	16.7	59	83.9	0.81 (0.78-0.83)

Hypocalcemia defined as iCa <1.1 mmol/L, and AdjCa cutoff was 2.2 mmol/L.
AdjCa, adjusted calcium (mmol/L); Alb, Albumin concentration (g/L); AUC, area under the curve; NPV, negative predictive value; PPV, positive predictive value; Sens, sensitivity; Spec, specificity; Total Ca, Total calcium (mmol/L).

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