GGT Determination Flashcards
Where was GGT first identified?
Kidney tissue
Has the highest level of GGT
Renal tissue
Where does serum GGT originate?
Hepatobiliary system
TRUE or FALSE: GGT is elevated in liver diseases.
True
GGT levels may increase __-__ times the normal levels in intra- or post-hepatic biliary obstruction.
5-30
GGT is elevated - times than normal in infectious hepatitis.
2-5
GGT catalyzes the transfer of the gamma-glutamyl group from (substrate) ________________ to (acceptor) ______________ at a pH of 8.2. The product of the reaction is a yellow compound known as ________.
Substrate: L-gamma-glutamyl-p-nitroanilide Acceptor: Glycylglycine Product: p-nitroaniline
The rate of increase in absorbance is directly __________ to GGT activity at ___ nm.
proportional
405 nm
Methods for GGt activity determination
- Szasz-Rosalki IFFC Recommended Method
- Persijn and Van der Silk Method
- Goldberg Method
This is the reference method for GGT activity determination
Szasz-Rosalki IFFC Recommended Method
In 1963, they introduced gamma-glutamyl-p-nitroanilide as a substrate.
Orlowski and Meister
They added glycylglycine as an acceptor in 1966, resulting in an increase in reaction rate.
Kulhanek and Dimov
L-gamma-glutamyl-3-carboxyl-4-nitroanilide + glyclyglycine = 5-amino-2-nitrobenzoate
Szasz-Rosalki IFFC Recommended Method
TRUE or FALSE: Szasz and Persijn substituted L-gamma-glutamyl-p-nitroanilide with GLUPAC, which is a more stable reagent.
True
_____________ has a better absorbance at 410 nm.
5-amino-2-nitrobenzoate
This assay is based on the hydrolysis of L-gamma-glutamyl-3-carboxyl-4-nitranilide.
Persijn and Van der Silk Method
TRUE or FALSE: L-gamma-glutamyl-3-carboxyl-4-nitranilide can directly produce its own chromogen.
True
This method uses L-gamma-glutamyl-beta naphthylamide as a substrate
Goldberg Method
The preferred specimen for GGT determination.
Non-hemolyzed serum
Aside from non-hemolyzed serum, this specimen type can also be used.
EDTA plasma
It may produce turbidity in the reaction.
Heparin
Decrease GGT activity by 1-15%
Citrate
Oxalate
Fluoride
Decreases GGT activity by 5-7%
Hemoglobin (100-500 mg/dl)
Serum GGT is stable for at least __ hrs. at room temp.
8
Serum GGT is stable for 1 month at ___
4 degrees Celsius
Serum GGT is stable for a year at _____
-20 degrees Celsius
Falsely elevate GGT levels
Barbiturate, phenytoin, and other anticonvulsant drugs
Exhibit negligible interference (<5%)
Bilirubin
What is the linearity of GGT determination methods?
up to 600 IU/L
If samples exceed the linearity limit, what should be done?
Samples should be diluted with an equal amount of saline and re-assayed.
Final results of diluted samples should be multiplied by __
2
The normal value for adult males
up to 45 IU/L
The normal value for adult females
up to 30 IU/L
