*Procedure
Pipette into cuvettes
Distilled water
Sample
standard
Reagent 2
URIC ACID
Enzymatic Colorimetric Method
*principle
Enzymatic colorimetric determination of Uric Acid
acccording to the following reactions:
Uricase
Uric Acid + 2H2O + O2
Allantoine + CO2 + 2 H2O2
POD
2H2O2 + 4 - Aminoantipyrine + DHBS
Red Quinone
+ 4 H2O
Intensity of the colour is direct proportional to the Uric Acid
concentration
Reagents composition, Contents and Safety warnings
Standard
Uric Acid
(R1)
Reagent
(R2)
Pipes buffer, pH:
7.00
4-Aminoantipyrine
Peroxidase
Ascorbate oxidase
357 μmol/l
(6.0mg/dl)
50 mmol/l
Blank
20 µl
Storage and Stability of Reagents
Store the kit at 2 - 8°C
All the components are stable until the stated expiration
date if stored
tightly closed, refrigerated.
Preparation and Stability of Working solution
Reagents liquid and ready to use.
Bring reagents at Room Temperature before use
Safety precautions
For in vitro diagnostic use only.
Do not pipette by mouth.
Exercise the normal precautions required for handling
laboratory reagents.
standard
20 µl
1 ml
1 ml
20 µl
1 ml
Mix,incubate for 5 minutes at 37°C or 10 minutes at Room
Temperature.
Read the absorbance of Calibrator and Samples against
the Blank at Wavelength of 510 nm (500 - 550 nm).
Note: With opalescent samples, a Sample Blank should be
carried out preparing a fourth cuvette with 25 μl of sample
and 1 ml of Buffer.
Mix and read the absorbance.
This Absorbance is subtracted from the Sample
Absorbance
*Calculation
Serum, plasma
A Sample
URIC ACID (mg/dl) =
x standard Value
Quality control
Control sera are recommended to monitor the performance
of manual and automated assay procedures.
Notes
With a Blank absorbance against water > 0.070 discard the
reagents
Bibliography
Fossati P., Prencipe L., Berti G., Clin. Chem. 26, 277
(1980)
A standard
For in vitro diagnostic use only.
Urine
A Sample
URIC ACID (mg/dl) =
0.37 mmol/l
≥1500 U/l
≥1600 U/l
Sample
Mean
SD
CV%
Control 1
4.32
0.040
0.94
Control 2
10.04
0.160
1.63
E. ACCURACY
Comparation between this method (y) and another
commercial one(x) gave the following results:
N = 20 r = 0.98 y = 1.0038x + 0.1494
F. INTERFERENCES
Haemoglobin up to 100 mg/dl does not interfere
Bilirubin up to 30 mg/dl does not interfere
Triglycerides up to1500 mg/dl do not interfere
Ascorbic Acid interferes in little quantity also
x standard Value x10
A standard
Urine/24h
URIC ACID (mg/dl)
URIC ACID (mg/24h) =
x Volume 24 h (ml)
100
Reference values
Serum:
Male
3.4 - 7.0 mg/dl
Female 2.4 - 5.7 mg/dl
Urine:
250 - 750 mg/24 h
These values should only be used as a guideline.
Each laboratory should establish its Normal Reference
Range
Performance Characteristics
A. LINEARITY LIMIT
The reaction is linear up to 25 mg/dl
For higher value dilute sample1:2 with normal saline,
repeat the test and multiply the value by 2
B. DETECTION LIMIT
Values less than 0.15 mg/dl give non - reproducible results
C. INTRA - ASSAY PRECISION (N=20 replicates)
Mean (mg/dl)
SD
CV%
Control 1
4.30
0.048
1.12
Control 2
10.00
0.248
2.48
D. INTER - ASSAY PRECISION (20 replicates for 3 days)
The following symbols are used on labels
For in vitro diagnostic use
Use by (last day of the month)
Temperature limitation
Batch Code
www.betalab-eg.com