Diabetes Screening and Diagnosis

Standards of Care in Diabetes - 2025

• Slides created, reviewed, and approved by the American Diabetes Association (ADA).
• Slides can be used in presentations without permission if content is unaltered, and proper attribution is to the ADA
• Commercial use or reproduction in print requires the ADA's permission.

Evidence-Grading System

• Table 1 outlines the ADA evidence-grading system for standards of care

ADA Grading System

• A: Clear evidence from adequately powered, well-conducted, generalizable randomized controlled trials, including multicenter trials and meta-analyses with quality ratings.
• B: Supportive evidence from adequately powered, well-conducted randomized controlled trials, including trials at one or more institutions and meta-analyses with quality ratings.
• C: Supportive evidence from poorly controlled or uncontrolled studies, including randomized clinical trials with methodological flaws, observational studies with high bias potential, and case series with historical controls.
• E: Expert consensus or clinical experience, even with conflicting evidence where the weight of evidence supports the recommendation.

Table of Contents

• Improving Care and Promoting Health in Populations
• Diagnosis and Classification of Diabetes
• Prevention or Delay of Diabetes and Associated Comorbidities
• Comprehensive Medical Evaluation and Assessment of Comorbidities
• Facilitating Positive Health Behaviors and Well-being to Improve Health Outcomes
• Glycemic Goals and Hypoglycemia
• Diabetes Technology
• Obesity and Weight Management for the Prevention and Treatment of Type 2 Diabetes
• Pharmacologic Approaches to Glycemic Treatment
• Cardiovascular Disease and Risk Management
• Chronic Kidney Disease and Risk Management
• Retinopathy, Neuropathy, and Foot Care
• Older Adults
• Children and Adolescents
• Management of Diabetes in Pregnancy
• Diabetes Care in the Hospital
• Diabetes and Advocacy

Diagnostic Tests for Diabetes

• Diagnose diabetes based on A1C or plasma glucose criteria
• Plasma glucose criteria include:
  • Fasting plasma glucose (FPG)
  • 2-h plasma glucose (2-h PG) during a 75-g oral glucose tolerance test (OGTT)
  • Random glucose accompanied by classic hyperglycemic symptoms/crises
• If hyperglycemia is not obvious, diagnosis needs confirmation via testing.

Diagnosis of Diabetes Criteria

• A1C: ≥6.5% (≥48 mmol/mol), performed in a NGSP-certified and DCCT-standardized laboratory.
• FPG: ≥126 mg/dL (≥7.0 mmol/L), with fasting defined as no caloric intake for at least 8 hours.
• 2-h PG during OGTT: ≥200 mg/dL (≥11.1 mmol/L), using a glucose load equivalent to 75 g anhydrous glucose in water, as described by the WHO.
• Random plasma glucose: ≥200 mg/dL (≥11.1 mmol/L) in an individual with classic symptoms of hyperglycemia.
• Unequivocal hyperglycemia diagnosis requires two abnormal results from the A1C and FPG obtained at the same or at different time points

A1C Screening and Diagnosis for Diabetes

• The A1C test should be performed using a method certified by the National Glycohemoglobin Standardization Program (NGSP) traceable to the Diabetes Control and Complications Trial (DCCT) reference assay.
• Point-of-care A1C testing for diabetes screening and diagnosis should only use devices approved for diagnosis by the FDA in Clinical Laboratory Improvement Amendments-certified laboratories with moderate complexity testing or higher, performed by trained personnel.
• When blood glucose values and A1C test results differ significantly, evaluate potential problems or interferences with either test
• When there are issues that alter the relationship between A1C and glycemia, plasma glucose criteria should be used to diagnose diabetes
• Conditions causing changes with A1C:
  • Some hemoglobin variants
  • Pregnancy (second and third trimesters and the postpartum period)
  • Glucose-6-phosphate dehydrogenase deficiency
  • HIV
  • Hemodialysis
  • Recent blood loss or transfusion
  • Hemolysis
  • Erythropoietin therapy

Criteria Defining Prediabetes

• A1C: 5.7-6.4% (39-47 mmol/mol)
• FPG: 100 mg/dL (5.6 mmol/L) to 125 mg/dL (6.9 mmol/L) (IFG)
• 2-h PG during 75-g OGTT: 140 mg/dL (7.8 mmol/L) to 199 mg/dL (11.0 mmol/L) (IGT) Risk of developing diabetes is continuous and increases at the higher end of the range

Classification

• Classify people with hyperglycemia appropriately to aid in personalized management

Types of Diabetes

• Type 1 diabetes is caused by autoimmune destruction of β-cells, leading to insulin deficiency. This includes latent autoimmune diabetes in adults.
• Type 2 diabetes is caused by nonautoimmune progressive loss of adequate insulin secretion paired with a case history of insulin resistance.
• Other specific types of diabetes
  • Monogenic diabetes syndromes
  • Diseases of the exocrine pancreas
  • Drug- or chemical-induced diabetes
• Gestational diabetes mellitus is diagnosed in the second or third trimester of pregnancy that was not overt diabetes prior to gestation

Staging Type 1 Diabetes

• Stage 1: Autoimmunity, normoglycemia, and presymptomatic with multiple islet autoantibodies and normal A1C levels
• Stage 2: Autoimmunity, Dysglycemia, and presymptomatic with multiple islet autoantibodies and dysglycemia. Dysglycemia includes IFG, IGT, increased A1C, or 10% increase in A1C.
• Stage 3: Autoimmunity, overt hyperglycemia, and symptomatic with diabetes by standard criteria and potentially absent autoantibodies.

Screening Criteria for Diagnosing Diabetes in Asymptomatic Adults

• Testing should be considered in adults with overweight or obesity (BMI ≥25 kg/m² or ≥23 kg/m² in individuals of Asian ancestry) with one or more risk factors.
• Risk factors include:
  • First-degree relative with diabetes
  • High-risk race, ethnicity, and ancestry
  • History of cardiovascular disease
  • Hypertension (≥130/80 mmHg or on therapy)
  • HDL cholesterol level <35 mg/dL (<0.9 mmol/L) and/or triglyceride level >250 mg/dL (>2.8 mmol/L)
  • Individuals with polycystic ovary syndrome
  • Physical inactivity
  • Other clinical conditions associated with insulin resistance
• People with prediabetes should be tested yearly
• Testing for people with GDM should be tested every 1-3 years
• Begin testing at age 35 for all other people
• Testing should be at a minimum of 3 years if results are normal
• Individuals in other high-risk groups (e.g., HIV, exposure to high-risk medicines, evidence of periodontal disease, history of pancreatitis) should be monitored closely

Decision Cycle for Person-Centered Glycemic Management in Type 2 Diabetes

• Review and agree on a management plan
• Assess key person characteristics
• Consider specific factors that impact choice of treatment
• Use shared decision-making to create a management plan
• Implement a management plan
• Agree on a management plan
• Provide ongoing support and monitoring

Comprehensive Diabetes Medical Evaluation Considerations

Components of comprehensive diabetes medical evaluations:

• Assess past medical and family histories.
• Assess diabetes history for characteristics, review of previous treatments, and severity of past hospitalizations.
• Check for family history of diabetes in a first-degree relative, autoimmune disorders
• Enquire about any complications or common comorbidities. Specifically obesity, OSA, and MASLD.
• Check last dilated eye exam and dental visit
• Complete disability assessment.
• Assess personal history of autoimmune disease
• Check interval history for changes in medical or family history

Diabetes Medical Evaluation Behavioral Considerations

• Eating patterns and weight history
• Assess familiarity with carbohydrate counting
• Physical activity and sleep behaviors; screen for OSA
• Tobacco, alcohol, and substance use

Diabetes Medical Evaluation Medication and Vaccination Information

• Current medication plan
• Medication-taking behavior, including rationing medications and/or medical equipment
• Medication intolerance or side effects
• Complementary and alternative medicine use
• Vaccination history and needs

Diabetes Medical Evaluation Tech and Social Life Information

• Assess use of health apps, online education, patient portals, etc.
• Assess glucose monitoring meter/CGM and their data use,
• Review insulin pump settings/glucose data
• Identify existing social supports, surrogate decision maker, and social determinants of health
• Evaluate personal lifestyle.

Physical Examinations for Diabetics Assessments

• Height, weight, and BMI; growth and pubertal development in children and adolescents
• Blood pressure determination
• Fundoscopic and skin examination
• Thyroid palpitation
• Comprehensive foot examination
• Check pedal pulses and screen for PAD with ABI if a PAD diagnosis change management

Laboratory Evaluations for Diabetics

• Laboratory Evaluation:
  • A1C, if the results are not available within the past 3 months
  • Lipid profile, including total, LDL, and HDL cholesterol and triglycerides
  • Liver function tests (i.e., FIB-4)+
  • Spot urinary albumin-to-creatinine ratio
  • Serum creatinine and estimated glomerular filtration rates
  • Thyroid-stimulating hormone in people with type 1 diabetes
  • Celiac disease in people with type 1 diabetes
  • Vitamin B12 if taking metformin for >5 years
• CBC with platelets
• Assess serum potassium levels in people with diabetes on ACE inhibitors, ARBs, or diuretics
• Conduct assessments of calcium, vitamin D, and phosphorous for appropriate people with diabetes.

Diabetes Complication Assessments

• Essential components for evaluating a patient:
  • Assessing ASCVD and heart failure history
  • Assess ASCVD risk factors and 10-year ASCVD risk.
  • Assessing hypoglycemic risk with patients to determine proper targets and set realistic goals
  • Setting proper lipid and blood glucose goals to better regulate blood pressure
  • Setting weight management and physical goals

Therapeutical Diabetes Plans

• Plans consist of lifestyle management in accordance with a registered dietician nutritionist referral to diabetes and specialist
• In taking a pharmacological approach, therapies should consist of cardiovascular focused and kidney health
• Implement medicine with weight management tools and therapies, as well as surgical referrals

Glycemic Assessment Recommendations

• Assessing glycemic status using A1C and CGM such as time in range, time above range, and time below range
• Assessing glycemic status at least two times a year or more frequently when the person has issues meeting glycemic goals or with recent treatment changes

Glycemic Targets

• Glycemic targets should be individualized on the preference with the person of diabetes which includes lifestyle and health benefits
• Factors to consider when assessing someone are health effects, hypoglycemic risks, and benefits
• In some cases stringent goals may be difficult, while in cases some less stringent goals may be beneficial

Glycemic Goals

• An A1C goal of <7% (<53 mmol/mol) is appropriate for many nonpregnant adults without severe hypoglycemia or frequent hypoglycemia affecting health or quality of life.
• A goal with time in range is >70% in people using CGM is appropriate for many nonpregnant adults.
• When reassessing glucose or A1C goals, consider the individual shown to improve outcomes

Cardiovascular Disease for Type 2 Diabetics

• To improve cardiovascular levels SGLT2 inhibitors or GLP-1 RAs can be initiated independently of current A1C goal
• SGLT2 or GLP-1 should be considered and switched once a high A1C level has reached an appropriate level to benefit the patient safely

Summary Of Glycemic Goals

• A1C goals should be <7.0% (<53 mmol/mol) while preprandial capillary plasma glucose is 80-130 mg/dL
• When looking to check Glucose levels via capillary plasma the goal should be <180

Hypoglycemia Treatment

• If a person is hypoglycemic (70 mg/dL), administer some form of carbohydrates that include glucose to improve levels
• Try not to provide any high fat products.

Hypoglycemia Assessment, Prevention, and Treatment

• History should be reviewed at every appointment for all individuals taking medications with prevention techniques
• A health professional team should screen and provide assistance to those taking medication
• Glucagon should be given to patients who are high risk or taking and should be given by family members to assist

Classification of Hypoglycemia

• Levels of hypoglycemia:
  • Level 1: Glucose <70 mg/dL
  • Level 2: Glucose <54 mg/dL
  • Level 3: Glucose <54 leading to severe mental, potentially needing medical assistance

Glycemic Crisis Review

• A review of the crisis is needed in order to provide education on recognition, in order to prevent these events from happening

Treatment for Type 1 Diabetes

• Treat patients with subcutaneous infusion from prandial (injected) and basal A is recommended to help improve outcomes
• Insulin analogs are a priority in helping reduce hypoglycemia and its risk.
• Automated insulin delivery systems should be offered to all adults with type 1 diabetes

Type 1 Diabetes Self Care

• To improve outcomes through self care one must receive proper medication to help match the carbohydrate, fat, and protein intake
• A plan must be considered to take action and reevaluate

Management for Type 2 Diabetes

• A health care routine focused on helping and setting time to best manage the overall result and outcome
• A center person for the situation can better coordinate the outcome and manage the overall system

Device Principles for Diabetics

• Provide devices for people with diabetes based on their specific needs and wants.
• For type 1 diabetics, CGM should be offered as early as possible.
• Make sure that all patients receiving a new device are highly trained and can handle it properly.

Recommendations

• Students should be supported while in school
• Recommend early initiation of CGM depending on needs
• Raw data should be available depending on the type of device

This lesson covers laboratory standards for A1C tests, situations where plasma glucose criteria are preferred, and the approach for discrepancies between blood glucose and A1C. It further explains the importance of classifying hyperglycemia and the use of fructosamine or continuous glucose monitoring (CGM).