Mix 1volume of Reagent 2with 1volume of Reagent 3
Working solution stability: 7 days at 2 - 8oC.
Bring reagents at Room Temperature before use.
Creatinine
Kinetic Colorimetric Method
principle
CREATININE in a basic picrate solution forms a
colored complex.
The Rate of Absorbance increase is direct
proportional to Creatinine concentration
in serum
The kinetic procedure reduces the effects of the
interfering substances.
Reagents composition
Reagent 1
STANDARD
Reagent 2
Sodium Hydroxide
Borate Buffer
Reagent3
Picric Acid
2 mg/dl
600 mmol/l
31 mmol/l
Safety precautions
For in vitro diagnostic use only.
Do not pipette by mouth.
Exercise the normal precautions required for
handling laboratory reagents.
*Procedure
Wavelength
Hg 510 nm (500 - 520)
Cuvette
light path: 1cm
Temperature
30/37o C
Adjust the instrument to zero against air or distilled
water
Macro Method Semi micro Method
Pipette into cuvettes
Sample Standard Sample Standard
Sample
200 µl
100 µl
Standard
200 µl
100 µl
Working Solution
2 ml
2 ml
1 ml
1 ml
Mix, transfer in cuvette, thermostat at 30 or 37oC,
wait for 30 seconds and read the first Absorbance
(A1) of Calibrator and Samples at Wavelength of 510
nm.
After 2 minutes read the second Absorbance (A2)
and calculate the difference  A = (A2 - A1)
72 mmol/l
The Reagent 2 is classified as C = corrosive
Content: SODIUM HYDROXIDE
Risk
• R34 Causes burns
• S26 In case of contact with eyes, rinse
immediately with plenty of water
and seek medical advise
• S45 In case of accident or if you feel unwell,
seek medical advice immediately (show the
label where possible)
• S61 Avoid release to the environment. Refer to
special instruction/safety data sheets
• S36/37/38 Wear suitable protective clothing,
gloves and eye/face protection
Storage and Stability of Working solution
All the Components are stable until the stated
expiration date if stored tightly closed.
Preparation and Safety of Working solution
Reagents liquid and ready to use
*Calculation
Children< 2 years
0.3 - 0.6
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 till to 25 mg/dl
For higher value dilute sample 1:2 with Distilled
Water, repeat the test and multiply the result 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
1.3385
0.036 2.72
Control 2
3.7180
0.108 2.92
D. INTER - ASSAY PRECISION (20 replicates for 3
days)
Mean
SD
CV%
Control 1
1.34
0.05
3.47
Control 2
3.71
0.05
1.39
E. ACCURACY
Comparation between this method (y) and another
commercial one (x), gave the following results:
N = 20 r = 0.990417 y = 0.96x + 0.024
F. INTERFERENCES
Haemoglobin till to150 mg/dl does not interfere
Bilirubin till to15 mg/dl does not interfere
Triglycerides till to1500 mg/dl do not interfere
Serum
A Sample
Creatinine (mg/dl) = ————— x Standard Value
Standard
Urine
A Sample
Creatinine (mg/dl) = ———— x Standard Value x 20
A Standard
Urine/24h
Creatinine in Urine (mg/dl)
Creatinine (g/24h) = —————————— x Urine Volume 24 h (lt)
100
Quality Control
Control sera are recommended to monitor the
performance of manual and
automated assay procedures
Bibliography
1.Henry, R.J.: Clinical Chemistry: Principles and
Techniques, Harper & Row.N.Y.,287 (1964).
Clearance
For in vitro diagnostic use only.
Creatinine Urine (mg/dl) x Volume Urine 24 h (ml) 1.73
Clearance (ml/min.) =
x
Creatinine Serum (mg/dl) x 1440
S
2
S = Body area in m
The following symbols are used on labels
Use by (last day of the month)
Reference values
Serum (mg/dl) Urine (g/24 h) Clearance (ml/min)
Male
Female
0.8 - 1.4
0.7 - 1.2
For in vitro diagnostic use
1- 2
0.8 - 1.8
97 - 135
88 - 128
Temperature limitation