OGTT Phenotypes

The OGTT assesses dynamic response to a glucose load rather than an overnight steady state. Some insulin-resistant patients can have normal fasting and post-load glucose, causing glucose-only screening to miss them. OGTT results can be confounded by hydration, exercise, sleep, and acute illness. Routine OGTT utility is limited when labs report glucose without insulin at each time point. Identifying the insulin-resistant normal-glucose phenotype requires measuring insulin alongside glucose at multiple OGTT time points. A multi-time-point OGTT can reveal glucose normalization speed, insulin release patterns, and glucose-insulin mismatch.