Final answer:
Confirmatory testing for extreme blood glucose levels indicated by glucose meters, such as hypoglycemia or hyperglycemia, is typically performed using a glucose tolerance test (GTT) in a laboratory setting. The GTT provides accurate diagnosis and understanding of the underlying mechanisms affecting glucose regulation, such as hormone resistance in Type 2 diabetes.
Step-by-step explanation:
Definitive testing for apparent hypoglycemia (<40mg/dl) or severe hyperglycemia (>500mg/dl) detected by glucose meters requires laboratory confirmation through more accurate blood glucose testing. This is often done by conducting a glucose tolerance test (GTT), which is a more definitive method for diagnosing diabetes mellitus. In this test, a patient's fasting blood glucose level is measured after consuming a controlled glucose solution, and then blood glucose levels are monitored over time to assess the body's ability to regulate glucose. The GTT helps to discern between different conditions such as defective insulin receptors or excessive insulin antagonists affecting blood sugar regulation.
It's important to note that portable blood glucose meters used at home or in clinical settings provide a quick snapshot of blood glucose levels, but for extreme values or diagnosis, confirmatory tests like the GTT are essential. For those with Type 2 diabetes, this might involve assessing hormone resistance, where target cells do not respond adequately to insulin, leading to abnormally high or low blood sugar levels.