Hemoglobin A1C (HbA1c)

Hemoglobin A1C is a blood test that reflects your average blood sugar levels over the previous 2-3 months by measuring the percentage of hemoglobin molecules in your red blood cells that have glucose attached to them. While useful for monitoring long-term blood sugar trends (normal is below 5.7%, prediabetes is 5.7-6.4%, and diabetes is 6.5% or higher), A1C can underestimate glucose problems in women with PCOS—approximately 30% of women with PCOS show normal A1C values while still demonstrating impaired glucose tolerance on an oral glucose tolerance test. For this reason, A1C should be used alongside OGTT rather than as a standalone screening tool for metabolic risk in PCOS.