glucose test ms. ibtisam alaswad ms. nour a. taim

Glucose test

Ms Ibtisam alaswad Ms Nour A taim

Introduction

Blood glucose _bull The main sugar that the body makes from the food in

the diet Glucose is carried through the bloodstream to provide energy to all cells in the body Cells cannot use

glucose without the help of insulin bull Glucose is a simple sugar (a monosaccharide) The body

produces it from protein fat and in largest part carbohydrate Ingested glucose is absorbed directly into the blood from the intestine and results in a rapid increase in blood glucose Glucose is also known as dextrose

The Objectives to be achieved

bull To understand the principle to spectrophotometer A spectrophotometer is used to measure the amount of

light a sample (be it liquid or solid) absorbs Light is passed through the sample and a detector measures the intensity of that light that passes through the sample and hits that detector

bull To determine the blood glucose concentration as an application of spectrophotometer use

bull To know how to use some devices in the lab

The principle of Glucose test

Glucose present in the plasma is oxidized by the enzyme glucose oxidase (GOD) to gluconic acid with the liberation of hydrogen peroxide which is converted to water and oxygen by the enzyme peroxidase (POD)4_aminophenazone an oxygen acceptor takes up the oxygen and together with phenol forms a pink coloured chromogen which can be measured at 515nm

Specimen type collection and storage bull Plasma is the specimen of choice for glucose estimation

Plasma glucose levels have been checked to be quite stable for 6 hours at room temperature (25 -350C) in the authorrsquos laboratory It is important that plasma should be separated from the cells soon after collection preferably within 1 hour

bull About 2 ml of the patientrsquos blood should be collected by venipuncture into a tube containing a mixture of potassium ethylene diaminetetraacetate (EDTA) sodium fluoride at a ratio 12 (WW) Five mg of the mixture is adequate for 2 ml of blood The tube should be gently but thoroughly shaken for complete mixing

Procedure

BlankStandardSampleControl

Standard __10microl ____

Sample ____10microl __

Control ______10microl

Reagen 10 ml 10 ml 10 ml __

Procedure

bull Mix Incubate 10 min at 37ordmc or 30 min at room temperature Measure the ABSORBANCE at 505nm (490-550) against the blank

bull The color is stable 30min

Discussion

bull CalculationGlucose (mgdl) = (Abs sampleAbs standard) standard

concbull LinearityThis method is linear up to 500mgdlIf the glucose concentration is greater than 500mgdl dilute

the sample 12 with saline solution and repeat the determination and multiply the result by 2

bull Reference valueSerum 55-110mgdl Plasma glucose Fasting 70 ndash110 mgdl

How to Use a Micropipettor

bull The micropipettor is used to transfer small amounts (lt 1 ml) of liquids The scales on micropipettors are in microliters (1000μl = 1 ml)


1 Never exceed the upper or lower limits of these pipettors

2 Set the desired clockwise to increase volume by turning the centrally located rings volume or counterclockwise to decrease volume

3 Place a tip on the discharge end of the pipettor NOTE If sterile conditions are necessary do

not allow the pipet tip to touch any object (including your hands)


4 The plunger will stop at two different positions when it is depressed each point indicate the volume to be taken

5 Depress the plunger until you feel the initial resistance and insert tip into the solution just barely below the surface of the liquid and not as deep as possible


6 Carefully and slowly release plunger NOTE If the solution you are pipetting is viscous allow the pipet tip to fill to final volume before removing it from solution to avoid the presence of bubbles in the plastic tip which will result in an inaccurate volume

7 Discharge the solution into the appropriate container by depressing plunger This time depress the plunger to the point of initial resistance wait one second and then continue pressing the plunger as far as it will go in order to discharge the entire volume of solution8Remove tip by pressing down on the tip discarder

NOTES

1048766 Never point a pipettor up This may cause liquid to run down into the pipettor destroying it

1048766 When withdrawing liquids with the pipettor always release the plunger slowly This prevents liquid from rushing into the end of the pipette and clogging it up This is especially important with large volume pipettors (200-1000 μl)

1048766 Be sure you use the proper size tip for each pipettor1048766 Always use a new tip for each different liquid1048766 Use the correct pipettor for the volume that is to be

dispensed Never use the 200-1000 μl pipette to dispense volumes below 200 μl going below or above the range of the micropipettor may damage the instrument

Introduction

Blood glucose _bull The main sugar that the body makes from the food in

the diet Glucose is carried through the bloodstream to provide energy to all cells in the body Cells cannot use

glucose without the help of insulin bull Glucose is a simple sugar (a monosaccharide) The body

produces it from protein fat and in largest part carbohydrate Ingested glucose is absorbed directly into the blood from the intestine and results in a rapid increase in blood glucose Glucose is also known as dextrose











Procedure






Procedure



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Procedure



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Procedure



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glucose test ms. ibtisam alaswad ms. nour a. taim

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