Investigations for type1 diabetes mellitus

Investigations are important to diagnose the diabetes and to identify the type of the diabetes as well. Types of investigations are;

1. hematological
2. genetic studies


Hematological investigations (Blood tests)

• Blood glucose: This is the mainstay of test to diagnose. Results are interpreted according to the
• Serum electrolytes: to identify the renal involvement.
• Urinalysis for glucose, ketones, and protein: these are important to detect renal involvement and diabetes ketoacidosis.
• White blood cell count and blood and urine cultures to rule out infections.
• Glycosylated hemoglobin (Hb)/Hb A1c ; this is a good test to recognize the glycemic control
• Oral glucose tolerance test with insulin levels: Although this test usually is considered unnecessary to make the diagnosis in type 1 DM, with the dramatic increase of type 2 diabetes in the young population, assessment of insulin secretion may become more important.
• To determine whether the individual has type 1 rather than type 2 DM, an insulin and/or C-peptide level below 5 µU/mL, or 0.6 ng/mL, suggests type 1. C-peptide is formed during conversion of proinsulin to insulin. A high positive titre of glutamic acid decarboxylase antibodies also suggests type 1 DM. An exception is the individual with type 2 DM who presents with a very high glucose, eg, above 300 mg/dL, who temporarily has a low insulin and/or C-peptide level but who will recover insulin production once normal glucose is restored.
• Islet cell antibodies
• Thyroxine (T4) and thyroid antibodies

Genetic studies

• HLA typing may be considered.