ADA guidelines are published every January. Please find below the 2017 recommendations on how to properly categorize various types of diabetes mellitus.

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Diabetes Care

ADA Guidelines

January 2017

ADA CLASSIFICATION:

Diabetes can be classified into the following general categories:

Type 1 diabetes (due to autoimmune β-cell destruction, usually leading to absolute insulin deficiency)
Type 2 diabetes (due to a progressive loss of β-cell insulin secretion frequently on the background of insulin resistance)
Gestational diabetes mellitus (diabetes diagnosed in the 2nd or 3rd trimester of pregnancy that was not clearly overt diabetes prior to gestation)
Specific types of diabetes due to other causes, e.g., monogenic diabetes syndromes (such as neonatal diabetes and maturity-onset diabetes of the young [MODY]), diseases of the exocrine pancreas (such as cystic fibrosis), and drug- or chemical-induced diabetes (such as with glucocorticoid use, in the treatment of HIV/AIDS, or after organ transplantation)

Recommendations

PREDIABETES (similar to DM2)

Testing for prediabetes and risk for future diabetes in asymptomatic people should be considered in adults of any age who are overweight or obese (BMI ≥25 or ≥23 in Asian Americans) and who have one or more additional risk factors for diabetes.
For all people, testing should begin at age 45 years.
If tests are normal, repeat testing carried out at a minimum of 3-year intervals is reasonable.
To test for prediabetes, fasting plasma glucose, 2-h plasma glucose after 75-g oral glucose tolerance test, and A1C are equally appropriate.
Testing for prediabetes should be considered in children and adolescents who are overweight or obese and who have two or more additional risk factors for diabetes.

POST-TRANSPLANTATION DIABETES MELLITUS

Patients should be screened after organ transplantation for hyperglycemia, with a formal diagnosis of posttransplantation diabetes mellitus being best made once a patient is stable on an immunosuppressive regimen and in the absence of an acute infection.
The oral glucose tolerance test is the preferred test to make a diagnosis of posttransplantation diabetes mellitus.

CYSTIC FIBROSIS–RELATED DIABETES

Annual screening for cystic fibrosis–related diabetes with oral glucose tolerance test should begin by age 10 years in all patients with cystic fibrosis not previously diagnosed with cystic fibrosis–related diabetes.
A1C as a screening test for cystic fibrosis–related diabetes is not recommended.
Patients with cystic fibrosis–related diabetes should be treated with insulin to attain individualized glycemic goals.
Beginning 5 years after the diagnosis of cystic fibrosis–related diabetes, annual monitoring for complications of diabetes is recommended.

POST-TRANSPLANTATION DIABETES MELLITUS

Patients should be screened after organ transplantation for hyperglycemia, with a formal diagnosis of posttransplantation diabetes mellitus being best made once a patient is stable on an immunosuppressive regimen and in the absence of an acute infection.
The oral glucose tolerance test is the preferred test to make a diagnosis of posttransplantation diabetes mellitus.

MONOGENIC DIABETES SYNDROMES

All children diagnosed with diabetes in the first 6 months of life should have immediate genetic testing for neonatal diabetes.
Children and adults, diagnosed in early adulthood, who have diabetes not characteristic of type 1 or type 2 diabetes that occurs in successive generations (suggestive of an autosomal dominant pattern of inheritance) should have genetic testing for maturity-onset diabetes of the young.
In both instances, consultation with a center specializing in diabetes genetics is recommended to understand the significance of these mutations and how best to approach further evaluation, treatment, and genetic counseling.

CYSTIC FIBROSIS–RELATED DIABETES

Annual screening for cystic fibrosis–related diabetes with oral glucose tolerance test should begin by age 10 years in all patients with cystic fibrosis not previously diagnosed with cystic fibrosis–related diabetes.
A1C as a screening test for cystic fibrosis–related diabetes is not recommended.
Patients with cystic fibrosis–related diabetes should be treated with insulin to attain individualized glycemic goals.
Beginning 5 years after the diagnosis of cystic fibrosis–related diabetes, annual monitoring for complications of diabetes is recommended.

POST-TRANSPLANTATION DIABETES MELLITUS

Patients should be screened after organ transplantation for hyperglycemia, with a formal diagnosis of posttransplantation diabetes mellitus being best made once a patient is stable on an immunosuppressive regimen and in the absence of an acute infection.
The oral glucose tolerance test is the preferred test to make a diagnosis of posttransplantation diabetes mellitus.

GESTATIONAL DM

Test for undiagnosed diabetes at the first prenatal visit in those with risk factors, using standard diagnostic criteria.
Test for gestational diabetes mellitus at 24–28 weeks [at the start of 3rd trimester] of gestation in pregnant women not previously known to have diabetes.
Test women with gestational diabetes mellitus for persistent diabetes at 4–12 weeks’ postpartum, using the oral glucose tolerance test and clinically appropriate nonpregnancy diagnostic criteria.
Women with a history of gestational diabetes mellitus should have lifelong screening for the development of diabetes or prediabetes at least every 3 years.
Women with a history of gestational diabetes mellitus found to have prediabetes should receive intensive lifestyle interventions or metformin to prevent diabetes.

MONOGENIC DIABETES SYNDROMES

All children diagnosed with diabetes in the first 6 months of life should have immediate genetic testing for neonatal diabetes.
Children and adults, diagnosed in early adulthood, who have diabetes not characteristic of type 1 or type 2 diabetes that occurs in successive generations (suggestive of an autosomal dominant pattern of inheritance) should have genetic testing for maturity-onset diabetes of the young.
In both instances, consultation with a center specializing in diabetes genetics is recommended to understand the significance of these mutations and how best to approach further evaluation, treatment, and genetic counseling.

CYSTIC FIBROSIS–RELATED DIABETES

Annual screening for cystic fibrosis–related diabetes with oral glucose tolerance test should begin by age 10 years in all patients with cystic fibrosis not previously diagnosed with cystic fibrosis–related diabetes.
A1C as a screening test for cystic fibrosis–related diabetes is not recommended.
Patients with cystic fibrosis–related diabetes should be treated with insulin to attain individualized glycemic goals.
Beginning 5 years after the diagnosis of cystic fibrosis–related diabetes, annual monitoring for complications of diabetes is recommended.

POST-TRANSPLANTATION DIABETES MELLITUS

Patients should be screened after organ transplantation for hyperglycemia, with a formal diagnosis of posttransplantation diabetes mellitus being best made once a patient is stable on an immunosuppressive regimen and in the absence of an acute infection.
The oral glucose tolerance test is the preferred test to make a diagnosis of posttransplantation diabetes mellitus.

TYPE 2 DIABETES (similar to Pre-DM)

Testing for type 2 diabetes in asymptomatic people should be considered in adults of any age who are overweight or obese (BMI ≥25 or ≥23 in Asian Americans) and who have one or more additional risk factors for diabetes.
For all people, testing should begin at age 45 years.
If tests are normal, repeat testing carried out at a minimum of 3-year intervals is reasonable.
To test for type 2 diabetes, fasting plasma glucose, 2-h plasma glucose after 75-g oral glucose tolerance test, and A1C are equally appropriate.
Testing for type 2 diabetes should be considered in children and adolescents who are overweight or obese and who have two or more additional risk factors for diabetes.

GESTATIONAL DM

Test for undiagnosed diabetes at the first prenatal visit in those with risk factors, using standard diagnostic criteria.
Test for gestational diabetes mellitus at 24–28 weeks [at the start of 3rd trimester] of gestation in pregnant women not previously known to have diabetes.
Test women with gestational diabetes mellitus for persistent diabetes at 4–12 weeks’ postpartum, using the oral glucose tolerance test and clinically appropriate nonpregnancy diagnostic criteria.
Women with a history of gestational diabetes mellitus should have lifelong screening for the development of diabetes or prediabetes at least every 3 years.
Women with a history of gestational diabetes mellitus found to have prediabetes should receive intensive lifestyle interventions or metformin to prevent diabetes.

MONOGENIC DIABETES SYNDROMES

All children diagnosed with diabetes in the first 6 months of life should have immediate genetic testing for neonatal diabetes.
Children and adults, diagnosed in early adulthood, who have diabetes not characteristic of type 1 or type 2 diabetes that occurs in successive generations (suggestive of an autosomal dominant pattern of inheritance) should have genetic testing for maturity-onset diabetes of the young.
In both instances, consultation with a center specializing in diabetes genetics is recommended to understand the significance of these mutations and how best to approach further evaluation, treatment, and genetic counseling.

CYSTIC FIBROSIS–RELATED DIABETES

Annual screening for cystic fibrosis–related diabetes with oral glucose tolerance test should begin by age 10 years in all patients with cystic fibrosis not previously diagnosed with cystic fibrosis–related diabetes.
A1C as a screening test for cystic fibrosis–related diabetes is not recommended.
Patients with cystic fibrosis–related diabetes should be treated with insulin to attain individualized glycemic goals.
Beginning 5 years after the diagnosis of cystic fibrosis–related diabetes, annual monitoring for complications of diabetes is recommended.

POST-TRANSPLANTATION DIABETES MELLITUS

Patients should be screened after organ transplantation for hyperglycemia, with a formal diagnosis of posttransplantation diabetes mellitus being best made once a patient is stable on an immunosuppressive regimen and in the absence of an acute infection.
The oral glucose tolerance test is the preferred test to make a diagnosis of posttransplantation diabetes mellitus.

TYPE 1 DIABETES

Blood glucose rather than A1C should be used to diagnose the acute onset of type 1 diabetes in individuals with symptoms of hyperglycemia.
Screening for type 1 diabetes with a panel of autoantibodies is currently recommended only in the setting of a research trial or in first-degree family members of a proband with type 1 diabetes.
Persistence of two or more autoantibodies predicts clinical diabetes and may serve as an indication for intervention in the setting of a clinical trial. Outcomes may include reversion of autoantibody status, prevention of glycemic progression within the normal or prediabetes range, prevention of clinical diabetes, or preservation of residual C-peptide secretion.

TYPE 2 DIABETES (similar to Pre-DM)

Testing for type 2 diabetes in asymptomatic people should be considered in adults of any age who are overweight or obese (BMI ≥25 or ≥23 in Asian Americans) and who have one or more additional risk factors for diabetes.
For all people, testing should begin at age 45 years.
If tests are normal, repeat testing carried out at a minimum of 3-year intervals is reasonable.
To test for type 2 diabetes, fasting plasma glucose, 2-h plasma glucose after 75-g oral glucose tolerance test, and A1C are equally appropriate.
Testing for type 2 diabetes should be considered in children and adolescents who are overweight or obese and who have two or more additional risk factors for diabetes.

GESTATIONAL DM

Test for undiagnosed diabetes at the first prenatal visit in those with risk factors, using standard diagnostic criteria.
Test for gestational diabetes mellitus at 24–28 weeks [at the start of 3rd trimester] of gestation in pregnant women not previously known to have diabetes.
Test women with gestational diabetes mellitus for persistent diabetes at 4–12 weeks’ postpartum, using the oral glucose tolerance test and clinically appropriate nonpregnancy diagnostic criteria.
Women with a history of gestational diabetes mellitus should have lifelong screening for the development of diabetes or prediabetes at least every 3 years.
Women with a history of gestational diabetes mellitus found to have prediabetes should receive intensive lifestyle interventions or metformin to prevent diabetes.

MONOGENIC DIABETES SYNDROMES

All children diagnosed with diabetes in the first 6 months of life should have immediate genetic testing for neonatal diabetes.
Children and adults, diagnosed in early adulthood, who have diabetes not characteristic of type 1 or type 2 diabetes that occurs in successive generations (suggestive of an autosomal dominant pattern of inheritance) should have genetic testing for maturity-onset diabetes of the young.
In both instances, consultation with a center specializing in diabetes genetics is recommended to understand the significance of these mutations and how best to approach further evaluation, treatment, and genetic counseling.

CYSTIC FIBROSIS–RELATED DIABETES

Annual screening for cystic fibrosis–related diabetes with oral glucose tolerance test should begin by age 10 years in all patients with cystic fibrosis not previously diagnosed with cystic fibrosis–related diabetes.
A1C as a screening test for cystic fibrosis–related diabetes is not recommended.
Patients with cystic fibrosis–related diabetes should be treated with insulin to attain individualized glycemic goals.
Beginning 5 years after the diagnosis of cystic fibrosis–related diabetes, annual monitoring for complications of diabetes is recommended.

POST-TRANSPLANTATION DIABETES MELLITUS

Patients should be screened after organ transplantation for hyperglycemia, with a formal diagnosis of posttransplantation diabetes mellitus being best made once a patient is stable on an immunosuppressive regimen and in the absence of an acute infection.
The oral glucose tolerance test is the preferred test to make a diagnosis of posttransplantation diabetes mellitus.