Laboratory tests Baseline laboratory tests for all patients include Complete blood count Electrolytes Renal function tests Rapid plasma reagin test Measurement of fasting plasma glucose, glycosylated hemoglobin (HbA1C), and sometimes a 2-hour glucose tolerance test Vitamin B12 and folate levels Thyroid-stimulating hormone (TSH) level Some clinicians include serum protein electrophoresis, especially if patients have a painful sensory neuropathy not explained by diabetes.