-GT
METHOD
Optimized Colorimetric. Kinetic.
PRINCIPLE
Optimized kinetic determination of

-glutamyl- transferase (

-GT). The increase of the absorbance at 405 nm, due to the formation of the 5-Amino-2nitrobenzoic acid, is proportional to the

-GT-activity.:
L-Gamma-glutamyl-3-carboxy-4-nitroanilide + Glycylglycine
<

-GT >
Gamma-glutamyl-glycylglycine + 5-Amino-2-nitrobenzoate
REAGENTS COMPOSITION
R1: Glycylglycine
R2: L-Gamma-glutamyl-3- carboxy-
4-nitroanilide
150 mmol/l
6 mmol/l
- PRECAUTIONS
- For in vitro diagnostic use only.
- The reagents contain < 0,95g/L sodium azide.
Avoid contact with skin and/or mucous membranes !
- Use clean or single use glass/plastic material to avoid contaminations.
STABILITY OF REAGENTS
When stored at 2 – 8 °C and protected from light, the reagents are stable until the expiry date printed on the labels.
PREPARATION OF WORKING REAGENT
- For the “Start Reagent-procedure”
the reagents R1 and R2 are ready for use for
- For the “Sample Start-procedure” with monoreagent mix R1 + R2 = 5 + 1
Stability : 1 month at 2 – 8 °C
1 week at 18 – 25 °C
SAMPLES
Serum free of hemolysis , plasma (EDTA/heparin)
REFERENCE VALUES U/L (37 °C)
Adults:
Female
9 – 36
Children:
1 Day – 6 Months 15 – 132
6 Months
– 1 Year 1 - 39
1 – 12 Years
13
– 18 Years
4 - 22
4 - 24
Male
12 - 64
12 - 122
1
– 39
3 – 22
2 - 42
Note: It is recommended for each laboratory to establish and maintain its own reference values. The given data are only an indication.
ASSAY PROCEDURES
Reagents can be used manually (see method below) and on most analyzers. Applications are available on request.
Wavelength :
Temperature :
Cuvette :
Read against air
405 nm (410)
37°C
1 cm light path

Sample Start Procedure / Monoreagent
Working reagent
Sample :
: 1 mL
5 0 µL
Mix and after a 1 minute incubation, measure the change of absorbance per minute (

A/min) during
3 minutes.
.

Start Reagent Procedure / R1-R2
R1 :
Sample :
Mix and wait 1 minute
1 mL
5 0 µL
R2 : 200 µL
Mix and after a 1 minute incubation, measure the change of absorbance per minute (

A/min) during
3 minutes.
CALCULATION
Sample Start/Monoreagent procedure :
405 nm : => Activity (U/L) =

A/min x 2210
Start reagent procedure :
405 nm =>: Activity (U/L) =

A/min x 2608
CALIBRATION & QUALITY CONTROL
For the calibration of automated analyzers Greiner
Multicalibrator is recommended, for quality control use Greiner normal and abnormal control, Unitrol I and Unitrol II .
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PERFORMANCE DATA (37°C)
- Analytical range
The reagent is linear up to changes of 0.1

A/min
- Detection limit
The detection limit is equal to 1 U/L
- Precision
Within-run reproducibility
Within series n = 20
Sample 1
Sample 2
Sample 3
Mean value
[U/L]
51,5
207
154
Between-run reproducibility
Day to day n = 20
Mean value
[U/L]
Standarddeviation
[U/L]
0,69
1,08
1,51
CV
[%]
1,33
0,52
0,98
CV
[%]
Sample 1
Sample 2
Sample 3
51,5
206
155
Standarddeviation
[U/L]
0,69
1,21
1,13
1,33
0,58
0,73
- Correlation
A comparative study has been performed between the Greiner method and another commercial reagent on 30 human serum samples. The parameters of linear regression are as follows: y = 0,988 x – 1,39 U/l r = 1,000.
BIBLIOGRAPHY
1. Szasz, G. Kinetic photometric method for serum gamma glutamyltranspeptidase. Clin. Chem., 15
(1969) 124.
2.
Shaw LM, Stromme JH, London JL, Theodorsen L.
International Federation of Clinical Chemistry,
(IFCC), Scientific Committee, Analytical Section.
IFCC methods for the measurement of catalytic concentration of enzymes. Part 4. IFCC method for gamma-glutamyltransferase [(gamma-glutamyl)peptide: amino acid gamma-glutamyltransferase, EC
2.3.2.2]. J Clin Chem Clin Biochem 1983;21:633-46.
3.
Thomas L. Clinical Laboratory Diagnostics. 1st ed.
Frankfurt: TH-Books Verlagsgesellschaft;
1998.p.80-6.
SYMBOLS USED
For in vitro diagnostic medical use
Batch Code
Use by
INTERFERENCES
- Ascorbic Acid: no interference up to 30 mg/dL
- Bilirubin: no interference up to 40 mg/dL
- Hemoglobin: no interference up to 500 mg/dL
- Triglycerides: no interference up to 2000 mg/dL
Temperature limitation
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