Is Fasting Blood Sugar Sufficient to Diagnose Diabetes?

I'm definitely a fan of gathering as much data as you can. But I guess some would argue that like, a fasting blood glucose is sufficient to diagnose. That is not really the case because we diagnose prediabetes and diabetes multiple ways. And so oftentimes, those people need to look at their diet. To me, I personally think fasting is a really useful spiritual tool.