In clinical trials in patients with T1D, the incidence of DKA was similar across SGLT2 inhibitors, with some evidence of higher incidence of DKA with increasing dose.3–5,7,8,15,16 Thus, the American Diabetes Association recommends stopping or delaying SGLT inhibitors in cases of ketonemia (defined by elevated BHB).17 Consistent with this recommendation and based on the results presented here, we suggest checking BHB levels in all insulin-using patients before initiating an SGLT inhibitor. The gene discussed is SLC5A2; the disease is type 1 diabetes mellitus.