Klompas et al. [12] used a large EHR including primary and specialty care providers to develop and validate a complex algorithm (type 1 to type 2 codes > 0.5 and prescription for glucagon, type 1 to type 2 codes > 0.5 with no oral hypoglycemic other than metformin, C-peptide negative, autoantibodies positive, or prescription for urine acetone test strips) that reported a 65% (36–100%) sensitivity and 88% (78–98%) PPV for T1D and 100% (99–100%) sensitivity and 95% (88–100%) PPV for T2D. The gene discussed is GCG; the disease is type 1 diabetes mellitus.