LAB2 - AST Flashcards
is one of several enzymes that catalyze the exchange of amino acids and oxo groupds between alpha amino acids and alpha oxo acids
aspartate aminotransferase
ast is widely distributed throughout the body tissues with significant amounts in the
heart or liver
lesser amounts of AST are found in
skeletal muscle, kidney, pancreas, spleen, lungs, ad brain.
in myocardial infarction, serum AST may begin to rise within ___ after onset,
6-8 hours
in myocardial infarction, serum AST may begin to rise within 6-8 hours after onset, and will peak _____
within 2 days
in what day will AST go back to normal once MI occured
on fourth to fifth day of post infarction
coditions we can found increase serum AST
hepatitis, liver necrosis, cirrhosis, and liver metastasis
he/she first reported a kinetic method for measuring AST activity in serum
KARMEN
Subsequently, karmen’s kinetic method of measuring AST was been modified by
Bergmeyer et. al.
the first reaction in AST determination
L-aspartate + 2-oxoglutarate
catalyze by AST
L- glutamate + oxalacetate
2nd reaction in AST determination
oxalacetate + NADH + H
catalyze by malate dehydrogenase
L-malate + NAD
AST activity is determined by measuring the rate of oxidation of NADH at ____ nm
340
lactate dehydrogenase is inlcuded in the reagent to convert ______ in the sample to lactate
endogenous pyruvate
reagents are stable until the expiration date on their respective labels if stored in what temperature
2-8 * C
appearance of reagent
clear and colorless
the working reagent is stable for how many weeks if stored in 2-8 *C
4 weeks
the working reagent is stable for how many days if stored in room temp
5 days
the working reagent should be discarded if the initial absorbance read against distilled water at 340 m is below
0.800
specimen of choice for ast
non hemolyzed serum
aside from yellow top or serum, what other tubes as can be used
edta treated plasma or heparinized plasma
whenever possible, specimens should be separated and analyzed on the day of collection
oki?
oki po
the enzyme in serum is reportedly stable for a minimum of how many days in 2-8 *C
7 days
hemolysis must be avoided as the concentration of AST in red cells is roughly how many times of serum
10 times
acceptable level of bilirubin
40 mg/dl
acceptable level of triglycerides
2000 mg/dl
the values are derived based on the
absorptivity micromolar extinction coefficient of NADH at 340 nm
if the absorbance is greater than 0.16, what should we do
1 part of sample with 9 parts isotonic saline and re assay, multiply the result by 10
what type of specimen may require the use of sample blank
grossly icteric or turbid sample
normal range
8-33 U/L
