Alanine Aminotransferase

Question 0

Contain sodium azide

Answer 0

Enzyme reagent (R1) and starting reagent (R2)

Question 1

Method for the determination of Alanine Aminotransferase (ALT)

Answer 1

Kinetic method (Expert Panel of the International Federation of Clinical Chemistry)

Question 2

Reference range

Answer 2

(Review)

Question 3

Reaction principle

Answer 3

1 2-oxoglutarate + L-alanine – (GPT) – L-glutamate + pyruvate
2 Pyruvate + NADH + H – (LDH) – L-lactate + NAD

Question 4

Contents

Answer 4

1 Reagent 1/Enzyme reagent

2 Reagent 2/Starting reagent

Question 5

Reagent start stability

Answer 5

The reagents are stable even after opening up to the stated expiry date when stored from light at 2-8 Celsius

Question 6

Procedure with sample start

Answer 6

For 12012: Pipette 2 mL from bottle 2 (starting reagent R2) into one bottle 1 (enzyme reagent, R1), mix thoroughly. The working reagent is stable for 4 weeks at 2-8 Celsius and 5 days at 15-25 Celsius.

Question 7

Loss of activity

Answer 7

1 Within 3 days at 4 Celsius: 10%

2 At 20-25 Celsius: 17%

Question 8

Specimen

Answer 8

1 Serum
2 Heparinized plasma
3 EDTA plasma

Question 9

Optical path

Answer 9

1 cm

Question 10

Wavelength

Answer 10

Hg 365 nm, 340 nm or Hg 334 nm

Question 11

Temperature

Answer 11

1 25 Celsius
2 30 Celsius
3 37 Celsius

Question 12

Measurement

Answer 12

Against air (decreasing absorbance)

Question 13

Procedure with sample start

Answer 13

Semi-micro method
Mix, read the absorbance after 1 minute and at the same time start the stop watch. Read the absorbance again exactly after 1, 2, and 3 minutes.

Question 14

Linearity

Answer 14

If the absorbance change per minute exceeds 0.160 at Hg 334 n/340 m or 0.080 at Hg 365 nm or if the activity is higher than 150 U/L at 25/30 Celsius or 280 U/L at 37 Celsius, dilute 0.1 mL of the sample with 0.9 mL physiological saline (0.9% and repeat the assay using this dilution). Multiply the result by 10.

Question 15

Result of analyzing sera with very high activities

Answer 15

Initial absorbance may be very low as most of the NADH will have been consumed before taking the first reading

Question 16

Factors for calculation

Answer 16

(Review)

Question 17

Measurements for absorbance changes per minute within 0.06-0.08 (Hg 365 nm) or 0.12-0.16 (Hg 334 nm, 340 nm) (procedure 1+2)

Answer 17

Only from the first 2 minutes are used for calculation (1 minute incubation, 2 minutes measurement)