A 50 year old obese female presented with recurrent candidial urinary infection & excessive thirst. She also gives history of frequent night time urination. Which is the first test you will prefer in this patient?

Given clinical scenario is suggestive of Diabetes mellitus For screening, FBS or HbA1c is recommended. Because the patient has symptoms, a random plasma glucose of >200 mg/dL is adequate to diagnose diabetes mellitus. Other criteria include: FBS >126 mg/dL HbA1c>6.4% 2-hour plasma glucose >200 mg/dL during an oral glucose tolerance test C-peptide- determine normal cleavage of insulin from its precursor Normal C-peptide level with hypoglycaemia- surreptitious insulin use Low C-peptide level with hyperglycemia- pancreatic failure.