Investigation in diabetes are aimed at diagnosing diabetes, monitoring its progression, and detecting complications. Here’s a comprehensive list of tests typically performed:
1. Diagnostic Test
Fasting Plasma Glucose (FPG): Measures blood glucose after an overnight fast.
Diabetes: ≥126 mg/dL (7.0 mmol/L)
Oral Glucose Tolerance Test (OGTT): Blood glucose is measured before and 2 hours after consuming a glucose-rich drink.
Diabetes: ≥200 mg/dL (11.1 mmol/L) after 2 hours
Random Plasma Glucose: A glucose level ≥200 mg/dL (11.1 mmol/L) with symptoms indicates diabetes.
HbA1c (Glycated Hemoglobin): Reflects average blood glucose over the past 2-3 months.
Diabetes: ≥6.5%
2. Monitoring Tests
Self-Monitoring of Blood Glucose (SMBG): Performed with a glucometer for day-to-day glucose levels.
Continuous Glucose Monitoring (CGM): Provides real-time glucose trends using a sensor.
Fructosamine: Reflects blood sugar levels over the past 2-3 weeks.
Ketone Testing: Done in cases of suspected diabetic ketoacidosis (DKA), especially in type 1 diabetes.
3. Investigations for Complications
Kidney Function Tests:
Urine Albumin-to-Creatinine Ratio (UACR): Detects microalbuminuria.
Serum Creatinine and eGFR: Assess kidney function.
Ophthalmologic Examination:
Fundoscopy to detect diabetic retinopathy.
Peripheral Neuropathy Assessment:
Monofilament testing, vibration tests, or nerve conduction studies.
Cardiac Evaluation:
Lipid Profile: Assess cardiovascular risk.
ECG or stress tests if cardiovascular disease is suspected.
Foot Examination:
Check for ulcers, infections, or vascular insufficiency.
4. Advanced Investigations (if indicated)
C-Peptide Levels: Helps differentiate between type 1 and type 2 diabetes.
Autoantibody Testing: Confirms type 1 diabetes (e.g., GAD, islet cell antibodies).
Insulin Levels: Occasionally used to assess insulin resistance or production.
Liver Function Tests: Evaluate for non-alcoholic fatty liver disease (NAFLD) associated with diabetes.
