What are the first line investigations for a diabetic patient?

First-Line Investigations for Diabetic Patients

The essential first-line investigations for diabetic patients include fasting blood glucose, HbA1c, urine albumin excretion, comprehensive eye examination, foot examination, and cardiovascular risk assessment. 1

Diagnostic Confirmation and Monitoring

• Fasting blood glucose should be measured as the first-line test for diabetes diagnosis, with values ≥1.26 g/L (7.0 mmol/L) on two occasions confirming diabetes 1
• HbA1c measurement is essential for diagnosing (≥6.5%) and monitoring long-term glycemic control 1
• Oral glucose tolerance test (OGTT) may be performed when needed, with plasma blood glucose ≥2 g/L (11.1 mmol/L) at 2 hours indicating diabetes 1

Renal Function Assessment

• Annual urine albumin excretion test should be performed in all type 2 diabetic patients starting at diagnosis and in type 1 diabetic patients with diabetes duration of ≥5 years 1
• Serum creatinine and estimated GFR (eGFR) should be measured to assess kidney function 1
• When ACE inhibitors, ARBs, or diuretics are used, monitor serum creatinine and potassium levels for changes 1

Ophthalmologic Evaluation

• Initial dilated and comprehensive eye examination by an ophthalmologist or optometrist should be performed:
  • Within 5 years after diagnosis for type 1 diabetes 1
  • Shortly after diagnosis for type 2 diabetes 1
• Subsequent examinations should be repeated annually, with less frequent exams (every 2-3 years) considered following normal eye exams 1

Foot Examination

• Annual comprehensive foot examination to identify risk factors for ulcers and amputations, including 1:
  • Inspection of feet
  • Assessment of foot pulses
  • Testing for loss of protective sensation using 10-g monofilament
  • Testing at least one of the following: vibration using 128-Hz tuning fork, pinprick sensation, ankle reflexes, or vibration perception threshold 1

Cardiovascular Risk Assessment

• Lipid profile including LDL cholesterol, HDL cholesterol, and triglycerides 1
• Blood pressure measurement to assess hypertension status 1
• Cardiovascular risk assessment to determine need for aspirin therapy and statin therapy 1

Additional Important Investigations

• Screening for distal symmetric polyneuropathy starting at diagnosis of type 2 diabetes and 5 years after diagnosis of type 1 diabetes 1
• Smoking status assessment as smoking cessation counseling should be a routine component of diabetes care 1
• Assessment for diabetes-related comorbidities including cardiovascular disease 1

Special Considerations

• For patients presenting with previously undiagnosed dysglycemia, investigations should determine whether the condition corresponds to pre-existing dysglycemia or stress hyperglycemia 1
• In patients with type 1 diabetes, consider evaluating for autoimmune conditions 1
• For patients on medications like metformin, regular monitoring of renal function and vitamin B12 levels is important 2

Pitfalls to Avoid

• Relying solely on fasting glucose without HbA1c can miss diagnoses 1
• Failing to screen for complications at diagnosis in type 2 diabetes, as many patients already have complications when diagnosed 1
• Not monitoring for hypoglycemia in patients on insulin or sulfonylureas 2
• Neglecting to assess blood glucose variability, which is important for preventing both acute and chronic complications 3