This document provides instructions for determining serum glucose levels using a glucose oxidase method. It begins with background information on glucose and its role in the body. It then describes the two main methods for collecting blood samples and discusses normal and abnormal glucose ranges. The principle of the glucose oxidase method is explained, where glucose is oxidized to produce a colored complex that can be measured. Finally, it provides the procedure for the test, including sample preparation and calculations to determine glucose concentration in mg/dL.

1. Determination of
Serum Glucose
5th Lab.
1st Stage Undergraduate Students
Lecturer's name: Msc.Hawta K. Abdulla
hawta.abdulla@su.edu.krd
2-Feb-2024
Knowledge University
College of Nursing
Nursing Departmrnt

2. • Background
• Glucose is a carbohydrate and energy source for
human body.
• Carbohydrate utilized mainly by cells in the form
of glucose.
• In blood quantitative estimation of glucose is
done with either whole blood, plasma, or serum
and several methods have been in use.
• Whole blood values are 10-13% lower than
Serum.

3. • Where does the glucose in your blood come
from?
• From your food, via the liver.
• From the breakdown of glucose stored as glycogen
in the liver.
• From protein and fat, converted in the liver to form
glucose (called gluconeogenesis).

4. • Methods for collecting blood for this test
1. Fasting Blood Sugar (FBS): the blood sample is collected
after the patient fasts for 6-8 hours or overnight.
2. Random Blood Sugar: blood collected any time without
prior preparation of the patient.

5. • Hyperglycemia:
Fasting blood glucose is more than 110 mg/dl
Occur in the following conditions:-
1- Diabetes mellitus. It’s the commonest cause of
hyperglycemia.
2- Chronic disease due to disorder of carbohydrate
metabolism.
3- Pancreatic disorders like chronic pancreatitis.
4- Stress (trauma, burns, surgery)
5- hyperactivity of thyroid or adrenal gland

6. • Hypoglycemia:
• Fasting blood glucose is less than 60 mg/dl.
Occur in the following conditions
1-Drug induced hypoglycemia like insulin over dose in
treatment of D.M,.
2-Fasting, starvation
3-Liver damage (alcoholism or disease)
4- several exercise
5- glycogen storage disease

7. Interpretation (Normal range)
Fasting blood glucose 70 – 110 mg/dl
Random blood glucose 140 – 200 mg/dl.
The appear limit increase with age and during
pregnancy.
Maintenance of a normal B. glucose level (70-110
mg/dl) is essential because some tissue for example
brain cells very dependent on extra cellular glucose
concentration.

8. Principle of the test :
•
Glucose present in the plasma is oxidized by the enzyme
(Glucose
oxidase
(
to
gluconic
acid with the liberation of hydrogen
peroxide, which is converted to water and oxygen by the enzyme
peroxidase
.
•
4-aminophenazone
,
an oxygen acceptor, takes up the oxygen and together
with phenol forms Red colored
complex
which can be measured at 500nm
.
Glucose oxidase (GOD) catalyzes the oxidation of glucose according to the following
equation :
GOD
Glucose + O2 Gluconic acid + H2O2
The hydrogen peroxide (H2O2) which is formed, in the presence of peroxidase (POD) reacts
with 4-aminophenazone and phenol, and gives rise to 4-benzoquinon monoiminophenazon
(a red dye)
POD
H2O2 + 4-aminophenazone + phenol 4 H2O + 4 p-benzoquinon
monoiminophenazone
(red color)

9. •
Procedure :
•
Centrifuge 3 ml EDTA blood, 2000 rpm for 10 min.
The plasma will be separated from the blood cells. Use plasma for sample.
•
Pipette into each of the three reaction tubes according to the following
table

10. • Mix the content of each tube well, then incubate them at 37oC for 10
minutes .
• Using cuvette tube, read the sample and standard absorbance against the
blank at 500 nm.
Calculation:
Calculate the concentration of BL in the provided fasting blood samples
using the absorbance reading of standard glucose and applying the following
equation:
Glucose (mg/dl) = (Abs. sample/Abs. standard)* standard conc. (100mgdl) .
Normal Range :
Normal (fasting BSL = 70 – 110 mg/dl)