The document discusses laboratory tests for diagnosing and monitoring diabetes mellitus. The main tests for diagnosis are urine glucose tests and blood tests measuring plasma glucose and HbA1c levels. Follow up monitoring includes using a glucometer to measure fasting and post-prandial blood glucose and repeating HbA1c tests. Tests for complications involve measuring ketone bodies for diabetic ketoacidosis and arterial blood gases and osmolality for hyperglycemic hyperosmolar syndrome. Long term complications are screened for through tests like microalbuminuria for nephropathy and lipid profiles for metabolic syndrome.

1. Laboratory diagnosis of
Diabetes Mellitus

2. Specific learning objectives
• Tests for diagnosis
• Cut off values as per ADA criteria
• Tests for follow up
• Tests during complications

3. For Diagnosis
• Urine tests – not recommended
– Fehling’s test
– Benedict’s test
– Glucose oxidase test
• Blood tests
– Serum/plasma glucose
– HbA1c

4. Fehling’s test

5. Benedict’s test

6. Glucose oxidase

7. Serum/ plasma glucose
• Glucose oxidase / glucose dehydrogenase

8. HbA1c

9. ADA guidelines 2015

11. Pre-diabetes

12. Glucose tolerance test
• 1.75 gm / kg body weight
• 75 gm in adults
• To be consumed in 5 minutes
• Samples at 0 and 2 hours

13. Oral glucose challenge test
• O’ Sullivan test
• Screening test – Gestational diabetes
• 24- 28 weeks of pregnancy
• 50 gm
• Samples at 1 hour
• Cut off – 140 mg/dl

15. Glucometer
• Glucose oxidase / dehydrogenase +
electrode

16. For dose adjustment
• Glucometer
• Fasting / postprandial
• HbA1c

17. Complications
• Diabetic ketoacidosis
• Ketone bodies
– Rohthera’s nitroprusside test

18. • Hyperglycemic hyperosmolar syndrome
• Arterial blood gas analysis
– Bicarbonate > 15 meq/L
– pH > 7.3
– Osmolality – >320 mOsm/kg

19. Nephropathy
• Microalbuminuria
• 30- 300 mg/24 hours
• Spot urine Albumin/creatinine ratio
• 30-300 ug/mg
• Renal function tests – urea / creatinine
• Kidney biopsy

20. Metabolic syndrome
• Lipid profile
– > Triglyceride
– > LDL
– < HDL

21. Misc. test
• Serum insulin
• Serum C-peptide
• Antibodies to
– Insulin
– Islet cell
– Glutamic acid decarboxlyase

22. Summary
• Tests to diagnose
– Plasma glucose
• Complications
– Ketones
– ABG
• Delayed complications
– Nephropathy
– Metabolic syndrome
• Misc tests