Type II Diabetes Mellitus III: Clinical Manifestations and Diagnosis

Type 2 diabetes develops gradually with early symptoms including frequent urination, excessive thirst, increased appetite, and unexplained weight loss. Fatigue and blurred vision may also appear over time. However, these symptoms are often mild or absent in early stages, making the condition difficult to detect without screening.

A fasting plasma glucose test measures blood glucose after at least eight hours without food. A level of 126 milligrams per deciliter or higher confirms diabetes, while 100-125 mg/dL suggests prediabetes. This test is one of the validated diagnostic methods for identifying type 2 diabetes.

In an oral glucose tolerance test, a patient consumes 75 grams of glucose, and plasma glucose is measured two hours later. A level of 200 milligrams per deciliter or more confirms diabetes, while 140-199 mg/dL indicates impaired glucose tolerance or prediabetes. This test is considered the most sensitive diagnostic method.

Hemoglobin A1c reflects average blood glucose over two to three months and does not require fasting. An HbA1c level of 6.5 percent or higher confirms diabetes, while 5.7-6.4% indicates prediabetes. This test is often preferred for convenience, though accuracy may be affected by hemoglobinopathies, anemia, or pregnancy.

Type 2 diabetes presents with fatigue, blurred vision, delayed wound healing, and recurrent infections, particularly candidal infections. Peripheral neuropathy may cause numbness or tingling in extremities. Most patients are overweight with associated hypertension and dyslipidemia, distinguishing type 2 diabetes from complications of diabetes mellitus that develop later.

A random plasma glucose level of 200 milligrams per deciliter or higher, combined with classic symptoms of hyperglycemia such as frequent urination, excessive thirst, and unexplained weight loss, confirms a diabetes diagnosis. This test does not require fasting and provides rapid diagnostic confirmation in symptomatic patients.

Routine screening for type 2 diabetes is recommended every three years in the general population. However, high-risk individuals should be screened annually. In asymptomatic individuals with abnormal results, confirmation on a separate day or with another test is necessary to establish a definitive diagnosis.