Diabetes Screening Recommendations

Primary Screening Recommendation

The American Diabetes Association recommends screening all adults beginning at age 45 years using fasting plasma glucose (FPG), repeating every 3 years if results are normal 1, 2
For adults younger than 45 years who are overweight or obese, screening should be performed if they have one or more additional diabetes risk factors 1, 2

All adults ≥45 years should be universally screened regardless of other risk factors 1, 2
Adults <45 years should be screened only if they are overweight/obese and have additional risk factors 1, 2
The American Diabetes Association recommends screening individuals with a first-degree relative with diabetes, high-risk race/ethnicity, history of cardiovascular disease, hypertension, low HDL cholesterol and/or high triglycerides, polycystic ovary syndrome, physical inactivity, history of gestational diabetes or delivery of a baby over 9 lbs, or other conditions associated with insulin resistance 1, 2

Fasting plasma glucose (FPG) is the preferred screening test because it is faster, easier to perform, more convenient and acceptable to patients, less expensive, and more reproducible than alternatives 1, 5, 6
Alternative acceptable tests include A1C (≥6.5% indicates diabetes; 5.7-6.4% indicates prediabetes) 1, 2 and 2-hour plasma glucose during 75-g oral glucose tolerance test (OGTT) (≥200 mg/dL indicates diabetes; 140-199 mg/dL indicates impaired glucose tolerance) 1, 2

Diabetes diagnosis can be made with FPG ≥126 mg/dL, 2-hour OGTT ≥200 mg/dL, or A1C ≥6.5% 1, 2, 7
Prediabetes diagnosis can be made with FPG 100-125 mg/dL, 2-hour OGTT 140-199 mg/dL, or A1C 5.7-6.4% 1, 2, 7

Normal results should be repeated at minimum 3-year intervals 1, 2
Prediabetes should be tested annually 1
History of gestational diabetes requires lifelong testing at least every 3 years 1
High-risk individuals may require more frequent testing based on risk profile 1, 2

In the absence of unequivocal hyperglycemia, abnormal results must be confirmed by repeat testing on a separate day 1, 3
If the same test is repeated and both results exceed the diagnostic threshold, diabetes is confirmed 1
If two different tests both exceed diagnostic thresholds, diabetes is confirmed 1

A1C should not be used in certain conditions where red blood cell turnover is altered, such as sickle cell disease, pregnancy, recent blood loss or transfusion, hemodialysis, or erythropoietin therapy 1, 4
Hemoglobin variants can interfere with A1C measurement, and marked discrepancies between A1C and plasma glucose should prompt consideration that the A1C assay may be unreliable for that individual 1
Fasting requirements for FPG testing define fasting as no caloric intake for at least 8 hours 1, 7

Community-based screening outside healthcare settings is not recommended due to lack of evidence for cost-effectiveness and potential for harm without adequate follow-up and interpretation 8

Testing should be considered in overweight or obese children and adolescents who have additional risk factors for diabetes, though the evidence base for A1C use in this population is limited 1