Glucose oxidase (GOD) converts glucose to gluconic acid. Hydrogen peroxide formed in this reaction, in presence of Peroxidase (POD), oxidatively couples with 4-aminoantipyrine and phenol to produce red quinoneimine dye. This dye has absorbance maximum at 505 nm. (500-550 nm.). The intensity of the colour complex is directly proportional to the concentration of glucose in specimen.
REAGENT STORAGE & STABILITY & HANDLING
- The kit should be stored at 2-8 degree C and is stable till the expiry date indicated on the label.
- The reagent and standard are ready-to-use and are stable till expiry when stored at 2-8 C. DO NOT FREEZE THE REAGENT.
- The reagent should be stored only in the amber bottle provided to protect it from direct light. This is critical because the reagent is light sensitive (auto oxidation of chromogen system by light and air). Before use swirl in the reagent gently. DO NOT SHAKE VIGOROUSLY.
- Over time, the reagent may develop a light pink colour, this is expected and does not affect the reagent performance.
- Contamination of the reagent should be strictly avoided. Should the reagent develop turbidity discard the reagent.
COMPONENTS & CONCENTRATION OF WORKING SOLUTION
Phosphate Buffer, pH 7.0
4 - amino antipyrine
Stabilizers and inactive ingredients
SPECIMEN COLLECTION & PRESERVATION
Blood should be collected in a clean dry container. Serum or plasma should be separated from the cells at the earliest possible (within 30 minutes), as the rate of glycolysis is approximately 7 mg% per hour at room temperature.
For plasma separation following anticoagulants may be used.
- EDTA 2 mg/ml of blood
- CITRATE 6 mg/ml of blood
- HEPARIN 200 IU/ml of blood
- OXALATE 3 mg/ml of blood
- SODIUM FLUORIDE 10 mg/ml of blood
Sodium Fluoride is preferred as anticoagulant due to the antiglycolytic activity. Higher concentration of Sodium fluoride i.e. more than 10 mg/ml blood should be avoided as it may inhibit the colour development.
Glucose is stable for 24 hours in neatly separated plasma and serum if the estimation is not possible within 24 hours then the specimen should be preserved at -10 Degree C and should be used within 30 days.
PROCEDURE FOR END-POINT
- Reaction type. End-Point
- Reaction Time 7 mins. at 37 Degree C / 15 mins. at R.T. (25-30 Degree C)
- Wavelength:505 nm. (500 - 550 nm.)
- Zero setting with Reagent Blank
- Sample volume: 0.01 ml (10 III )
- Reagent volume: 1.0 ml
- Standard concentration: 100 mg%
- Linearity: 500 mg/dl
Manual assay procedure
Prewarm at room temperature (25 -30 Degree C) the required amount of reagent before use.
Perform the assay as given below
1.0 ml procedure