Aspartate Aminotransferase acc. to IFCC with pyridoxal phosphate activation

Catalog Number: 05531446190

SYSTEM INFORMATION

INTENDED USE

In vitro test for the quantitative determination of aspartate aminotransferase (AST) with pyridoxal phosphate activation in human serum and plasma on Roche/Hitachi cobas c systems.

STORAGE AND STABILITY

ASTPM
Shelf life at 2-8 °C: See expiration date on cobas c pack label.
On-board in use and refrigerated on the analyzer: 2 weeks
On-board on the Reagent Manager: 0 hours
Diluent NaCl 9 %
Shelf life at 2-8 °C: See expiration date on cobas c pack label.
On-board in use and refrigerated on the analyzer: 4 weeks
On-board on the Reagent Manager: 24 hours

APPLICATION FOR SERUM AND PLASMA

cobas c 701/702 test definition
Assay type Rate A
Reaction time / Assay points 10 / 29-38
Wavelength (sub/main) 700/340 nm
Reaction direction Decrease
Units U/L (µkat/L)
Reagent pipetting Diluent (H2O)
R1 60 µL 51 µL
R3 20 µL 20 µL
Sample volumes Sample Sample dilution
Sample Diluent (NaCl)
Normal 9 µL
Decreased 9 µL 15 µL 135 µL
Increased 18 µL

CALIBRATION

Traceability: This method has been standardized against the original IFCC formulation using calibrated pipettes together with a manual photometer providing absolute values and the substrate-specific

absorptivity, e.7

Calibrators S1: H2OS2: C.f.a.s.
Calibration mode Linear
Calibration frequency 2-point calibrationafter reagent lot changeas required following quality control procedures

LIMITS AND RANGES

Measuring range

5-700 U/L (0.08-11.7 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

5 U/L (0.08 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 the lowest standard (standard 1 + 3 SD, repeatability, n = 21).

Values below the lower detection limit (< 5 U/L) will not be flagged by the instrument.

SPECIFIC PERFORMANCE DATA

Representative performance data on the 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

(n = 21) and intermediate precision (3 aliquots per run, 1 run per day, 20 days). The following results were obtained:

Results for intermediate precision were obtained on the master system cobas c 501 analyzer.

Repeatability MeanU/L (µkat/L) SDU/L (µkat/L) CV%
Precinorm U 46.2 (0.772) 1.1 (0.018) 2.4
Precipath U 159 (2.66) 1 (0.02) 0.6
Human serum A 18.0 (0.301) 1.2 (0.020) 6.8
Human serum B 142 (2.37) 1 (0.02) 1.0
Human serum C 607 (10.1) 2 (0.0) 0.4

Intermediate precision MeanU/L (µkat/L) SDU/L (µkat/L) CV%
Precinorm U 49.0 (0.818) 0.8 (0.013) 1.6
Precipath U 149 (2.49) 1 (0.02) 0.8
Human serum 3 40.7 (0.680) 1.3 (0.022) 3.1
Human serum 4 190 (3.17) 3 (0.05) 1.3

METHOD COMPARISON

AST values for human serum and plasma samples obtained on a Roche/Hitachi cobas c 701 analyzer (y) were compared with those determined using the corresponding reagent on a Roche/Hitachi cobas c 501 analyzer (x).

Sample size (n) = 308

Passing/Bablok14 Linear regression
y = 1.003x - 0.086 U/L y = 0.993x + 0.468 U/L
t = 0.888 r = 1.000
The sample activities were between 6.40 and 663 U/L (0.11 and 11.1 µkat/L).