How is prediabetes diagnosed?

    Last Updated: October 25, 2023

    Prediabetes is diagnosed based on either fasting plasma glucose, 2-hour plasma glucose during a 75-gram oral glucose tolerance test (OGTT), or HbA1c. According to the American Diabetes Association, an individual should be diagnosed with prediabetes if they have one of the following:[1]

    • Fasting glucose of 100–125 mg/dL (5.6–6.9 mmol/L)
    • 2-hour glucose during an OGTT of 140–199 mg/dL (7.8–11.0 mmol/L)
    • HbA1c of 5.7%–6.4%

    Notably, the World Health Organization defines the lower limit for impaired fasting glucose as 110 mg/dL (6.1 mmol/L).

    Evidence suggests that an OGTT is the most sensitive diagnostic test for prediabetes, and reliance on either fasting glucose or HbA1c alone may result in significant underdiagnosis of prediabetes.[2][3]

    References

    1. ^American Diabetes Association Professional Practice Committee2. Classification and Diagnosis of Diabetes: Standards of Medical Care in Diabetes-2022Diabetes Care.(2022 Jan 1)
    2. ^Meijnikman AS, De Block CEM, Dirinck E, Verrijken A, Mertens I, Corthouts B, Van Gaal LFNot performing an OGTT results in significant underdiagnosis of (pre)diabetes in a high risk adult Caucasian population.Int J Obes (Lond).(2017-Nov)
    3. ^Sacks DBA1C versus glucose testing: a comparison.Diabetes Care.(2011-Feb)