Table 2.

Evaluation of SpHb accuracy among the study groups.

Measures	Normal (n = 127)	Mild-to-moderate (n = 87)	Severe (n = 82)	P-value
Bias (g/dL)	0.20 (− 2.59 to 3.00)	0.98 (− 1.38 to 3.35)	1.23 (− 1.16 to 3.63)	< 0.001
Concordance rate	92%	97%	95%
Major error rate*	27%	52%	61%	< 0.001
Possible missed transfusion (SpHb > 7.0, Hb < 7.0 g/dL)	2%	8%	12%	< 0.001
Possible over-transfusion (SpHb < 7.0, Hb > 7.0 g/dL)	0.0%	0.2%	0.9%	NA†

The preoperative serum total bilirubin levels are classified into normal (< 1.2 mg/dL), mild-to-moderate hyperbilirubinemia (1.2–3.0 mg/dL), and severe hyperbilirubinemia (> 3.0 mg/dL ). Values are reported as the mean (95% limit of agreement), number, or proportion (percentage).

*Proportion of major errors that fall into the grey or red zone in the error grid analysis.

^†Not available because n > 500, but the number of each cell < 5.

SpHb non-invasive hemoglobin concentration, Hb hemoglobin.