Hemoglobin A1c (HbA1c) Glucose Test?

Sa

I failed my 1hr GD test & attempted to take the 3hr GD test but puked my guts up 45mins in so my Dr is giving me this blood test instead, but why have women suffer through the 3hr glucose test when THIS is an option?! I’m confused..I guess it tests your glucose levels for the past 3 months & she said there’s no reason for me to fast, why isn’t this an option from the get go?! Anyone else have this test done? How much blood do they take?