Blood glucose testing Biochemistry Lab experiment

1. 1
Faculty of Medicine
Biochemistry lab
Blood Sugar Testing
Prepared By :
Diaa Mohammad Srahin .
Supervisor:Dr. Suheir Jabir.

2. 2
BLOOD SUGAR TESTING
Introduction
A bloodglucose testmeasuresthe amountof atype of sugar,calledglucose, in your blood. Glucose comes
fromcarbohydrate foods.Itis the mainsource of energyusedbythe body.Glucose istransported from the
intestines or liver to body cells via the bloodstream, and is made available for cell absorption via the
hormone insulin, produced by the body primarily in the pancreas.
Glucose levelsare usuallylowestinthe morning, before the first meal of the day, and rise after meals for
an hour or two by a few millimolar. Blood sugar levels outside the normal range may be an indicator of a
medical condition. A persistently high level is referred to as hyperglycemia; low levels are referred to as
hypoglycemia. Diabetesmellitus is characterized by persistent hyperglycemia from any of several causes,
and isthe most prominentdisease relatedtofailure of blood sugar regulation. Intake of alcohol causes an
initial surge in blood sugar, and later tends to cause levels to fall. Also, certain drugs can increase or
decrease glucose levels.
The body’s homeostatic mechanism keeps blood glucose levels within a narrow range. It is composed of
several interacting systems, of which hormone regulation is the most important. There are two types of
mutually antagonistic metabolic hormones affecting blood glucose level:
 Catabolichormones( suchas glucagon,cortisol andcatecholamines),whichincrease bloodglucose
 Anabolic hormones (such as insulin), which decrease blood glucose.
There are several different typesof bloodglucose tests:
Fasting bloodsugar (FBS): measuresbloodglucose afteryouhave noteatenforat least8
hours.It isoftenthe firsttestdone to checkfor prediabetes anddiabetes.
2-hour postprandial blood sugar: measuresbloodglucose exactly2hoursafteryou start
eatinga meal.Thisisnot a testusedto diagnose diabetes.Thistestisusedtosee if someone with
diabetes istakingthe rightamountof insulin withmeals.
Random blood sugar (RBS): measuresbloodglucose regardlessof whenyoulastate.
Several randommeasurementsmaybe takenthroughoutthe day.Randomtestingisuseful
because glucose levelsinhealthypeopledonotvary widely throughoutthe day.Bloodglucose
levelsthatvarywidelymaymeanaproblem.Thistestisalsocalledacasual bloodglucose test.
Oral glucose tolerance test : isusedtodiagnose prediabetes anddiabetes.Anoral glucose
tolerance testisa seriesof bloodglucose measurementstakenafteryoudrinkasweetliquidthat
containsglucose.Thistestiscommonlyusedtodiagnose diabetesthatoccursduring pregnancy
(gestational diabetes).Womenwhohadhigh bloodsugarlevels duringpregnancymayhave oral
glucose tolerance testsafterpregnancy.
HemoglobinA1c, or glycohemoglobin : measureshow muchsugar (glucose) isstuckto
redbloodcells.Thistestcan be usedto diagnose diabetes.Italsoshowshow well yourdiabetes
has beencontrolledinthe past2 to 3 monthsand whetheryourdiabetesmedicine needstobe
changed.The resultof your A1c testcan be usedto estimate youraverage bloodsugarlevel.Thisis
calledyourestimatedaverage glucose,orEAG.

3. 3
Objectives
1. To calculate glucose concentration in the unknown sample.
2. To observe concentration of previous sample and compare it with normal value from
scientific references.
Materials
 Spectrophotometer & its components (Light source, Prism, Detector, Photoelectric cell).
 Cuvettes & pipettes & test tubes.
 Monoreagent as a Blank solution.
 Sample (serum).
 Constant temperature incubator set at 37 ͦC.
Methods & Procedures
1- Reagents & samples were Bring to room temperature.
2- Three clean tubes were prepared for our experiment.
3- Materials were put in the labeled tubes as next table shown :
Tubes Blank Serum STD
Working Reagent 1.0 ml 1.0 ml 1.0 ml
serum pool * 10µL *
STD * * 10µL
4- Tubes were mixed and then put 5 minutes at 37 ͦC
5- The absorbance (A) of the sample & the standard was read at 500 nm against the reagent
blank.
6- Finally, calculations were used to determine the concentration of glucose in our sample &
compare it with reference values.
Results
In our experiment, weuse Trinder reaction, the glucoseis oxidized to D-gluconate
by the glucose oxidase(GOD) with the formation of hydrogen peroxide. In the
presenceof peroxidase (POD), a mixture of phenol and 4-aminoantipyrineis
oxidized by hydrogen peroxide, to form a red quinanelmine dye proportionalto the
concentration of glucose in the sample.

4. 4
C STD = 100 mg / dL A Sample = 0.757 A STD = 0.474
C glucose =
A Sample
A STD
∗ C STD in mg/ld.
C glucose =
0.757
0.474
∗ 100
= 159.71 mg/dL.
Discussion
In our experiment we were given an unknown concentration sample with glucose
results and analysis showed the sample to have 159.71 mg/dl glucose which is high
value comparing with normal range for an adult (70 - 105 mg/dL) or children with
normal range (60 – 110 mg/dL). So results show that our patient with hyperglycemia
because blood glucose more than normal range.
Conclusion
1. Metabolic activity of our bodies can be measured using this test.
2. The glucose level in the blood is maintained by diet uptake and regulatory
hormones such as insulin, glucagon, and epinephrine.
3. An abnormal increase in blood glucose level, referred to as hyperglycemia, can
be associated with diabetes mellitus and hyperactivity of thyroid, pituitary or
adrenal glands.
4. An abnormal decrease beyond the fasting level, referred to as hypoglycemia, is
observed in cases of insulin secreting tumors, mixedema, hypopituitarism,
Addison’s disease and conditions interfering with glucose absorption.