According to the Bland–Altman analysis, the bias for SpHb and total Hb was 0.20 (95% Limit of agreement, LoA: − 2.59 to 3.00) g/dL with a percentage error of 3%, 0.98 (95% LoA: − 1.38 to 3.35) g/dL with a percentage error of 11%, and 1.23 (95% LoA: − 1.16 to 3.63) g/dL with a percentage error of 20% for the normal, mild-to-moderate, and severe hyperbilirubinemia groups, respectively (P < 0.001) (Fig. 2, Table 2). The gene discussed is GSTM1; the disease is Hyperbilirubinemia.