What labs should be ordered for a 14-year-old African-American male with a hemoglobin A1c (HbA1c) of 6.2?

From the Guidelines

For a 14-year-old African-American male with a hemoglobin A1c of 6.2%, I recommend ordering a fasting plasma glucose test, oral glucose tolerance test, and a comprehensive metabolic panel. The fasting plasma glucose will help confirm if the patient has prediabetes or diabetes, while the oral glucose tolerance test provides information about how the body processes glucose. The comprehensive metabolic panel should include electrolytes, kidney function tests, and liver function tests to assess overall health status. Additionally, a lipid panel should be ordered to evaluate cholesterol levels, as dyslipidemia often accompanies glucose metabolism disorders. Thyroid function tests are also important to rule out thyroid disorders that can affect metabolism. Given the patient's age and ethnicity, testing for autoantibodies associated with Type 1 diabetes (GAD65, islet cell antibodies) may be valuable to distinguish between Type 1 and Type 2 diabetes. An HbA1c of 6.2% falls in the prediabetes range (5.7-6.4%), and African-American youth have higher rates of both Type 1 and Type 2 diabetes compared to other ethnic groups, as noted in the 2021 standards of medical care in diabetes 1. Early identification and intervention are crucial to prevent progression to diabetes and its complications. It is also important to consider the potential impact of hemoglobinopathies on A1C results, as noted in the 2019 standards of medical care in diabetes 1, and to use an A1C assay that is certified by the NGSP and standardized to the DCCT assay. The diagnosis of diabetes should be based on the criteria outlined in the 2019 standards of medical care in diabetes, which include an A1C of 6.5% or higher, a fasting plasma glucose of 126 mg/dL or higher, or a 2-hour plasma glucose of 200 mg/dL or higher during an oral glucose tolerance test 1. In this case, since the patient's A1C is below the diagnostic threshold, further testing is needed to determine the presence of diabetes or prediabetes. The oral glucose tolerance test and fasting plasma glucose test will provide more information about the patient's glucose metabolism and help guide further management. It is also important to consider the patient's overall health status and to order additional tests as needed to assess for potential complications of diabetes, such as kidney disease or dyslipidemia. By taking a comprehensive approach to diagnosis and management, we can help prevent the progression of diabetes and its complications in this patient. The 2011 diagnosis and classification of diabetes mellitus guidelines also support the use of A1C as a diagnostic tool, with a threshold of 6.5% 1. However, the 2021 guidelines provide more up-to-date information and should be prioritized in this case. Overall, the key is to use the most recent and highest-quality evidence to guide diagnosis and management, while also considering the individual patient's needs and circumstances.

From the Research

Labs to be Ordered

For a 14-year-old African-American male with a hemoglobin A1c (HbA1c) of 6.2, the following labs should be considered:

• Fasting glucose or oral glucose tolerance test to assess glucose control 2
• Lipid profile to evaluate for dyslipidemia, a component of metabolic syndrome 3
• Blood pressure measurement to assess for hypertension, another component of metabolic syndrome 3
• Liver function tests to evaluate for non-alcoholic fatty liver disease, which is associated with insulin resistance and metabolic syndrome 3
• Complete blood count (CBC) to evaluate for anemia or other hematologic abnormalities that may affect HbA1c levels 4
• Reticulocyte count to assess for erythrocyte turnover, which may affect HbA1c levels 4

Considerations for HbA1c Interpretation

• HbA1c levels may be higher in African-American individuals compared to Caucasian individuals at similar glucose levels 5, 6
• A labile form of HbA1c may be higher in African-American youth with type 1 diabetes compared to Caucasian patients at similar glucose levels 6
• HbA1c may not accurately reflect glucose control in individuals with certain hematologic conditions, such as beta-thalassemia minor 4

Additional Evaluations

• Assessment for metabolic syndrome, which is characterized by insulin resistance, hypertension, dyslipidemia, and central obesity 3, 2
• Evaluation for other conditions that may affect glucose metabolism, such as polycystic ovary syndrome (PCOS) or Cushing's syndrome 2