11 Preventive Health Screening Tests Doctors Recommend

6. Diabetes screening (A1C / fasting glucose)

Diabetes screening detects elevated blood sugar that can lead to complications if untreated. Screening is recommended for adults starting around age 35 for those at average risk, earlier or more often if you have overweight, family history, high blood pressure, or other risk factors (ADA; USPSTF). What to expect: common tests include an A1C blood test, which shows average blood sugar over a few months, or a fasting glucose test measured after an overnight fast. Preparation tips: for fasting glucose, avoid food and calorie-containing drinks for 8–12 hours before the test; the A1C usually does not require fasting. If results indicate prediabetes, clinicians will often recommend lifestyle changes like modest weight loss, increased daily activity, and dietary shifts that can delay or prevent progression to diabetes. Many clinics offer brief counseling or refer to community programs; consider scheduling tests at times that fit around work or family routines so follow-up is easier.