Prediabetes is a component of metabolic syndrome and is characterized by elevated blood sugar levels that fall below the threshold to diagnose diabetes mellitus.

The presence of glucose in the bloodstream triggers the production and release of insulin from the pancreas' beta islet cells.

[9] Prediabetes can be diagnosed with three different types of blood tests:[10] Levels above these limits would justify a diagnosis for diabetes.

[5] Hyperinsulinemia due to insulin resistance may occur in individuals with normal glucose levels and therefore is not diagnosed with usual tests.

[19] The implications of hyperinsulinemia is the risk of comorbidities related to diabetes that may precede changes in blood glucose,[20][21][16] including cardiovascular diseases.

The risk factors for which are listed below: The United States Preventative Services Task Force (USPSTF) recommends adults who are overweight/obese and aged 40–70 years old to get screened during visits to their regular physician.

The American Diabetes Association (ADA) recommends normal testing repeated every three years and recommends a larger range of people get tested: anyone over the age of 45 regardless of risk; an adult of any age who is obese or overweight and has one or more risk factors, which includes hypertension, a first degree relative with diabetes, physical inactivity, high risk race/ethnicity, Asian Americans with BMI of ≥23 kg/m2, HDL < 35 mg/dL or TG > 250 mg/dL, women who have delivered child >9 lbs or with gestational diabetes, A1c ≥ 5.7%, impaired fasting glucose (IFG) or impaired glucose tolerance (IGT).

[27] In the UK, NICE guidelines suggest taking action to prevent diabetes for people with a body mass index (BMI) of 30.

[28] A study based on a large sample of people in England suggest even lower BMIs for certain ethnic groups for the start of prevention, for example 24 in South Asian and 21 in Bangladeshi populations.

[33] Considering the possibility to recover from the prediabetic status but also this emotional struggle upon diagnosis, it is encouraged for higher risk patients to get tested early.

Having an additional screening option in the dental setting may offset some of the emotional struggle because it is more regularly visited and therefore has the potential to initiate earlier recognition and intervention.

[citation needed] The American College of Endocrinology (ACE) and the American Association of Clinical Endocrinologists (AACE) have developed lifestyle intervention guidelines for preventing the onset of type 2 diabetes:[citation needed] Prediabetes is a curable disease state, and people can routinely return to normoglycemia (normal glucose metabolism) with interventions.

[15][35] Intensive weight loss and lifestyle intervention, if sustained, may improve glucose tolerance substantially and prevent progression from IGT to type 2 diabetes.

Most involve the reduction of added sugars and fats but there remains a lack of conclusive evidence proving the best approach.

[7] This may also be considered in patients for whom lifestyle therapy has failed, or is not sustainable, who are at high-risk for developing type 2 diabetes, or who prefer to take a medication.

Evidence also supports thiazolidinediones but there are safety concerns, and data on newer agents such as GLP-1 receptor agonists, DPP4 inhibitors or meglitinides are lacking.

[9] Prediabetes is a risk factor for mortality and there is evidence of cardiovascular disease developing prior to a diagnosis of diabetes.

The IFCC supported a review to provide recommendations that encourage developing standards for CGM performance studies.