Catalog Number: 20764957322
Test ALTL, test ID 0-495
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.
| 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 | |
| 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 |
| 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 |
| 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 parameter | Diluent (H2O) | |
| R1 | 59 µL | 10 µL |
| Sample | 11 µL | 26 µL |
| SR | 17 µL | 9 µL |
| Total volume | 132 µL |
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 |
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 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).
Representative performance data on COBAS INTEGRA analyzers are given below. Results obtained in individual laboratories may differ.
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 % |
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). | ||