Age??? Diabetes comes in 2 basic forms. The children's form develops abruptly after a virus destroys Insulin production.They quickly loose sugar in the urine, eat & drink ravenously & loose 10lb in a week. The fluffy adults make Insulin but not enough and they gradually get into trouble over months or years.A glucose tolerance test or A1c can give you early indication on a teen, in pre teens a urine test.
More important tests. If you are going to poke your child for blood, ask that several important things be included to test blood fats, kidney, liver and thyroid as well as blood sugar: hga1c, fasting blood sugar, creatinine, bun, lipid panel, ast, alt, tsh. And do get your child's blood pressure monitored.