1. Fasting Plasma Glucose (FPG) Test

• Purpose: This test determines the glucose levels in the blood after an overnight fast.
• Procedure: A blood sample is taken only after the patient has fasted for a minimum of 8 hours.
• Diagnosis:

• Normal: <100 mg/dL
• Prediabetes: 100-125 mg/dL (5.6-6.9 mmol/L)
• Diabetes: ≥126 mg/dL (7.0 mmol/L)
  
  

2. Oral Glucose Tolerance Test

• Purpose: The test determines the body’s ability to absorb glucose.
• Procedure: The patient is kept on overnight fasting; the level of fasting blood glucose is measured, followed by the administration of a solution with a certain amount of glucose content; the blood glucose levels are measured at systematic time intervals over the succeeding two-hour period.
• Diagnosis:

• Normal: <140 mg/dL (7.8 mmol/L) after 2 hours
• Prediabetes: 140-199 mg/dL (7.8-11.0 mmol/L) after 2 hours
• Diabetes: ≥200 mg/dL (11.1 mmol/L) after 2 hours
  
  

3. Hemoglobin A1c (HbA1c) Test

• Purpose: It provides an average of blood glucose over the past 2-3 months
• Procedure: Blood sample taken; no fasting required
• Diagnosis:

• Normal: <5.7%
• Prediabetes: 5.7-6.4%
• Diabetes: ≥6.5%
  
  

4. Random Plasma Glucose Test

• Purpose: It measures the blood glucose at any time of day, irrespective of when the patient has last eaten.
• Procedure: The blood sample is taken at any random time of the day.
• Diagnosis:

• Diabetes: ≥200 mg/dL (11.1 mmol/L), along with symptoms of diabetes, such as increased urination, thirst, and unexplained weight loss.
  
  

5. Continuous Glucose Monitoring

• Purpose: Provides continuous measurement of glucose levels in the interstitial fluid.
• Procedure: A small sensor is placed under the skin near the abdomen or on the arm, which records the glucose levels throughout the day and night.
• Diagnosis: This helps diabetics to draw trends and patterns in their blood sugar levels.
  
  

6. C-Peptide Test

• Purpose: To measure the amount of C-peptide in the blood to have an estimate of the amount of insulin produced in the body.
• Procedure: Blood sample, no fasting
• Diagnosis: To differentiate between type 1 diabetes and type 2 diabetes.
  
  

7. Insulin Auto-antibodies Test

• Purpose: To test for antibodies against insulin
• Procedure: Blood sample, no fasting
• Diagnosis: Mainly for diagnosing type 1 diabetes or auto-immune response against insulin.
  
  

8. Urine Tests

• Purpose: This test detects glucose or ketones in the urine.
• Procedure: A urine sample is analyzed.
• Diagnosis: It suggests high blood sugar levels or diabetic ketoacidosis if it involves ketones.
  
  

9. Lipid Profile

• Purpose: It analyzes the quantity of cholesterol and triglycerides in the blood.
• Procedure: Blood sampling; usually requires fasting.
• Diagnosis: This test is very crucial for determining cardiovascular risk in people suffering from diabetes.
  
  

10. Kidney Function Tests

• Purpose: To evaluate the health and functioning of the kidneys, which may get affected by diabetes.
• Procedure: Collecting blood and urine samples.
• Laboratory tests (Diagnosis)
  • Serum Creatinine: This quantifies the creatinine content in the blood.
  • Urine albumin-to-creatinine ratio: The amount of albumin in the urine is measured.
    
    

These diagnostic tests are of great importance in the early detection, continuous monitoring, and good management of diabetes. These regular tests permit proper and informed decision-making by patients and health providers about treatment plans and changes to make in living habits so as to keep blood sugar levels under control and thus prevent complications.