GSTM1 and bronchopulmonary dysplasia: The AUC for CO-Hb levels between postnatal days 5 and 8 (0.882, standard error: 0.067, p = 0.002) indicated that CO-Hb levels may be a more useful marker than urinary oxidative stress markers for predicting moderate-to-severe BPD (Figure 5, Table 2).