Alanine Aminotransferase

Catalog Number: 20764957322

SYSTEM INFORMATION

Test ALTL, test ID 0-495

INTENDED USE

In vitro test for the quantitative determination of the catalytic activity of ALT (EC 2.6.1.2; L-alanine:

2-oxoglutarate aminotransferase) in human serum and plasma on COBAS INTEGRA systems.

This method sheet describes the application for ALT without pyridoxal phosphate activation (test ALTL,

0-495). The application for ALT activated with pyridoxal phosphate is described in the method sheet Alanine Aminotransferase Pyridoxal Phosphate Activated.

STORAGE AND STABILITY

Shelf life at 2-8 °C See expiration date on cobas c pack label
COBAS INTEGRA 400 plus system
On-board in use at 10-15 °C 12 weeks
COBAS INTEGRA 800 system
On-board in use at 8 °C 12 weeks

APPLICATION FOR SERUM AND PLASMA

COBAS INTEGRA 400 PLUS TEST DEFINITION

Measuring mode Absorbance
Abs. calculation mode Kinsearch
Reaction mode R1-S-SR
Reaction direction Decrease
Wavelength A/B 340/378 nm
Calc. first/last 39/64
Unit U/L

PIPETTING PARAMETERS

R1 59 µL 10 µL
Sample 11 µL 26 µL
SR 17 µL 9 µL
Total volume 132 µL

Pipetting parameter Diluent (H2O)
R1 59 µL 10 µL
Sample 11 µL 26 µL
SR 17 µL 9 µL
Total volume 132 µL

COBAS INTEGRA 800 TEST DEFINITION

Measuring mode Absorbance
Abs. calculation mode Kinsearch
Reaction mode R1-S-SR
Reaction direction Decrease
Wavelength A/B 340/378 nm
Calc. first/last 54/97
Unit U/L

PIPETTING PARAMETERS

Pipetting parameter Diluent (H2O)
R1 59 µL 10 µL
Sample 11 µL 26 µL
SR 17 µL 9 µL
Total volume 132 µL

CALIBRATION

Traceability: This method has been standardized against the original IFCC formulation, but without pyridoxal-5'-phosphate, using calibrated pipettes together with a manual photometer providing absolute values and the substrate-specific absorptivity, e.7

Calibrator Calibrator f.a.s.Use deionized water as zero calibrator.
Calibration mode Linear regression
Calibration replicate Duplicate recommended
Calibration interval Each lot and as required following quality control procedures

LIMITS AND RANGES

MEASURING RANGE

2-700 U/L (0.03-11.7 µkat/L)

Determine samples having higher activities via the rerun function. Dilution of samples via the rerun function is a 1:10 dilution. Results from samples diluted using the rerun function are automatically multiplied by a factor of 10.

LOWER LIMITS OF MEASUREMENT

Lower detection limit of the test:

2 U/L (0.03 µkat/L)

The lower detection limit represents the lowest measurable analyte level that can be distinguished from 0. It is calculated as the value lying 3 standard deviations above that of a zero sample (zero sample + 3 SD, repeatability, n = 30).

SPECIFIC PERFORMANCE DATA

Representative performance data on COBAS INTEGRA analyzers are given below. Results obtained in individual laboratories may differ.

PRECISION

Precision was determined using human samples and controls in an internal protocol with repeatability and intermediate precision (2 aliquots per run, 2 runs per day, 20 days).

The following results were obtained:

Level 1 Level 2
Mean 34.9 U/L 132 U/L
(0.583 µkat/L) (2.20 µkat/L)
CV repeatability 1.0 % 0.5 %
CV intermediate precision 1.5 % 1.9 %

METHOD COMPARISON

ALT values for human serum and plasma samples obtained on a COBAS INTEGRA 700 analyzer using the COBAS INTEGRA Alanine Aminotransferase reagent ALTL (y) were compared to those determined using commercially available reagents for ALT on a COBAS INTEGRA analyzer (x) and on an alternative manufacturer’s clinical chemistry system (x). Samples were measured in duplicate. Sample size (n) represents all replicates.

COBAS INTEGRA analyzer
Sample size (n) 236
Correlation coefficient (r) 1.00
(rs) 0.998
Linear regression y = 1.068x - 2.31 U/L
Passing/Bablok15 y = 1.055x - 1.82 U/L

Alternative system
Sample size (n) 224
Correlation coefficient (r) 1.00
(rs) 0.995
Linear regression y = 0.983x + 0.772 U/L
Passing/Bablok15 y = 0.982x + 0.856 U/L
The sample activities were between 3.7 and 496 U/L (0.062 and 8.27 µkat/L).