Name: Anastasija Anastasovska
Group: a2
Student number: 113
Date: 14.03.2023
Biochemistry I- first lab report
Determination of glucose and ketone levels in blood and urine
Introduction
The aim of this laboratory is to:
Learn how to determine the glucose levels at specific time points-the glucose tolerance test.
Learn how to detect glucose and ketone bodies using the dipstick test.
Determine trough lab work if a patient has increased blood glucose levels/ to see if the patient
has diabetes.
Glucose is a monosaccharide which plays a substantial role in the energy production of the human body.
It is also the main energy source for the brain.
In this lab we determined the levels of glucose in the blood to see if the patient has a pathological
condition, such as diabetes. Diabetes usually is characterized as having excess amounts of glucose in the
blood/hyperglycemia. The main types of diabetes are:
Diabetes type 1- the pancreas is incapable of producing insulin or makes a little amount of
insulin.
Diabetes type 2- the body teds to become resistant to the insulin that the pancreas produces.
Gestational diabetes- develops during pregnancy.
Prediabetic condition- although this is not defined as diabetes the patient has higher levels of
glucose in the blood and is considered in risk of developing diabetes.
Some common symptoms of patients that have diabetes are feeling thirsty, urination often, having less
energy than usual, blurry vision.
With the glucose tolerance test we can observe how the body responds to the intake of
sugar(glucose).The first sample that is obtained is a fasting blood sugar sample. Then the patient drinks
around 237 ml of a glucose solution containing 100 grams of sugar. Then blood is drawn at hour 2 after
administering the solution in the body.
Glucose in urine is detected when there are high levels of glucose in the blood or if the renal tubes that
reabsorb glucose are damaged. In order to detect the amount of glucose in the urine in this lab we used
ketostix. Ketostix detect the ketones in the urine, they change color accordingly to the ketone level found
in the urine.
Methodology- experiment 7.1
In this experiment we used 8 test tubes.
The following table will show what each test tube contained.
Standard glucose Serum Reagent
solution
Blank solution / / 2 ml
Standard solution 20µL / 2ml
Time 0 minutes / 20µL 2ml
Time 30 minutes / 20µL 2ml
Time 60 minutes / 20µL 2ml
Time 120 minutes / 20µL 2ml
Time 180 minutes / 20µL 2ml
Time 240 minutes / 20µL 2ml
After preparing each test tube we left each solution to incubate at room temperature for 10 minutes.
Then we zeroed the spectrometer using the blank solution and setting it at a wavelength of 510nm. At
the end we calculated the glucose values using the equation:
OD sample mg glucose
×100=
OD standard 100 ml blood
Methodology-experiment 7.2
This experiment was performed by the professor.
The first step was: we dipped one strip into the urine sample.
The second step was: after one minute we observed the color change at the end of the strip and we
compared the color to the colorimetric scale on the strip vial.
Methodology- experiment 7.3
This experiment was performed by the professor.
The first step was: we dipped the strip and watched as the color changed from pink to purple.
The second step was: we compared the color of the strip to the colorimetric scale on the vial.
Methodology-experiment 7.4
In a test tube we added 2 ml of urine and drops of iron chloride. We continued to add the reagent until
we observed a bright red color.
Results- experiment 7.1
Picture 1. Glucose tolerance test samples
Test tube Blank Standard 0 30 60 120 180 240
solution minutes minutes minutes minutes minutes minutes
OD 0.305 0.514 0.685 0.951 0.947 0.745 1.003 1.095
nm nm nm nm nm nm nm nm
Table 2. Absorbed doses for each sample.
Results- experiment 7.2 and 7.3
Test strip number 1: the colors for glucose when
compared to the colorimetric scale show that the
urine sample doesn’t have abnormal levels of
glucose and of ketone bodies (the reaction was
negative)
1 2
Test strip number 2: This test strip when
compared to the colorimetric scale shows us that
the level of glucose is ≥ 1000 mg/dL meaning
the test was positive.
We can observe the same thing with the levels of
ketone in the urine, the strip corresponds with
the ++ color of the vial meaning the test is
positive for ketone bodies.
Picture 2- detection of ketones and glucose in urine
using ketostix strips
Results- experiment 7.4
After putting the reagent into the solution we observed a red color-
we concluded that the reaction was positive (there were ketone
bodies in the urine)
Picture 3- Detection of ketones in urine
Gerhardt method
Discussion
There were minor problems while executing the experiments, there is a possibility of contaminated lab
equipment in the first experiment, we concluded this by comparing our glucose vs time graph with the
graph that was given in the presentation. Our graph doesn’t resemble the line for the graph in the
presentation that is given for diabetes. The values for time 180 minutes and 240 minutes should be lover
than the previous values but in our graph are higher.
For the other experiments, they were conducted without any difficulty, all according to lab protocol.
Answers to questions
Question 1
Glucose values of fasting serum glucose
OD sample mg glucose
×100=
OD standard 100 ml blood
0.685 nm mg glucose
×100=113 , 26
0.514 nm 100 ml blood
Question 2
Using the formula:
OD sample mg glucose
×100=
OD standard 100 ml blood
we calculated the values of glucose in the sample at different time frames.
0.685 nm mg glucose
For time 0 ' ×100=113 , 26
0.514 nm 100 ml blood
0.951 nm mg glucose
For time 30 ' ×100=185.01
0.514 nm 100 ml blood
0.947 nm mg glucose
For time 60 ' ×100=184.24
0.514 nm 100 ml blood
0.745 nm mg glucose
For time 120 ' × 100=1 44 ,94
0.514 nm 100 ml blood
1.003 nm mg glucose
For time 180 ' ×100=195,136
0.514 nm 100 ml blood
1.095 nm mg glucose
For time 240 ' ×100=213.03
0.514 nm 100 ml blood
Time Abnormal serum sample mg%
0 minutes- before glucose administration 113,26 mg%
30 minutes post glucose administration 185,01 mg%
60 minutes post glucose administration 184,24 mg%
120 minutes post glucose administration 144,94 mg%
180 minutes post glucose administration 195,13 mg%
240 minutes post glucose administration 213.03 mg%
Table 3. concentration of glucose in each sample used to construct graph.
Glucose tolerance test
250
213
195
200 185 184
Glucose mg/dL
150 144
113
100
50
0
0 50 100 150 200 250 300
Time minutes
Graph 1- glucose serum levels vs time
Question 3
Glucose Ketones Ketones
time Glukotest ketostix Gerhardt
Fasting Positive Positive ++ Positive (red
>1000(dark green color)
color)
Conclusion
By doing this lab we learned how diagnosis and regulation of hyperglycemia is evaluated.
In experiment 7.1 by doing the glucose tolerance test we concluded that our patient has abnormal
values of glucose levels in the blood, most likely suffering from diabetes millitus.
In experiment 7.2 by comparing the color of our strips to the colorimetric scale we concluded that the
levels of glucose in the urine are >1000.
In experiment 7.3 2 by comparing the color of our strips to the colorimetric scale we concluded that the
levels of ketone in the urine are positive ++.
In experiment 7.4 by observing the color change of the solution we concluded that the reaction is
positive because after adding the reagent a red color was observed.
