1. BIOCHEMISTRY Blood Glucose

2. Determination of Blood Glucose (BG)
BG is determined by 2 methods:
1- Oxidation method ( enzymatic method):
Principle
-Glucose +O2 + H2O Glucose oxidase Gluconic acid + H2O2
-H2O2 + phenol + amino-4-antipyrine Peroxidase Quinoneimine +H2O

3. Determination of Blood Glucose: Oxidation Method
Procedure
Sample
name
Stand.
name
Serum
0.1 ml
0.1 ml
Stand.
1 ml
1 ml
Reagent
Mix , then incubate at 37°C for 10 min.
Read the absorbance of sample & stand. at λ= 505 nm
against blank (reagent)

4. Calculation Glugose (mg/dl) = Sample absorbance x conc of standard
Stand. Absorbance
Normal level
Fasting: mg/dl ( mmol/L)

5. Interpretation of the results
If BG >110 mg/dl HYPERGLYCEMIA
Causes:
1-Diabetis mellitus
2-Acromegaly
3-Acute stress
4-Adrenal hyperactivity (Cushing's syndrome)
5- Hyperthyroidism
6- Pancreatic cancer or pancreatitis
7- Drugs: e.g. corticosteroids

6. Interpretation of the results: cont.
If BG <70 mg/dl HYPOGLYCEMIA
Causes:
1- Insulin overdose
2- Hypothyroidism & hypopituitarism
3- Adrenal insufficiency (Addison's disease)
4- Liver diseases
5- Starvation

7. Renal glucose threshold
Definition:
-The blood glucose concentration at which the kidneys start to excrete glucose into the urine
-BG level of 180 mg/dl is called Renal Glucose Threshold
Glucoseurea
Appearance of glucose in urine (occurs when BG conc. > 180 mg/dl)

8. Renal glucose threshold