Cholinesterase Gen.2

Catalog Number: 04498577190

SYSTEM INFORMATION

Test CHE2, test ID 0-021

INTENDED USE

In vitro test for the quantitative determination of the catalytic activity of cholinesterase (EC 3.1.1.8; acylcholine acylhydrolase) in serum and plasma

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 4 weeks
COBAS INTEGRA 800 system
On-board in use at 8 °C 4 weeks

APPLICATION FOR SERUM AND PLASMA

COBAS INTEGRA 400 PLUS TEST DEFINITION

Measuring mode Absorbance
Abs. calculation mode Kinetic
Reaction mode R1-S-SR
Reaction direction Decrease
Wavelength A/B 409/659 nm
Calc. first/last 43/52
Unit U/L

PIPETTING PARAMETERS

Diluent (H2O)
R1 120 µL
Sample 2 µL 5 µL
SR 24 µL
Total volume 151 µL

Diluent (H2O)
R1 120 µL
Sample 2 µL 5 µL
SR 24 µL
Total volume 151 µL

COBAS INTEGRA 800 TEST DEFINITION

Measuring mode Absorbance
Abs. calculation mode Kinetic
Reaction mode R1-S-SR
Reaction direction Decrease
Wavelength A/B 409/659 nm
Calc. first/last 60/75
Unit U/L

PIPETTING PARAMETERS

Diluent (H2O)
R1 120 µL
Sample 2 µL 5 µL
SR 24 µL
Total volume 151 µL

CALIBRATION

Traceability: This test is standardized against a reference method using a manual application of the butyrylthiocholine/hexacyanoferrate (III) method on a photometer and the published molar absorptivity of hexacyanoferrate (III).3

Calibrator Calibrator f.a.s.
Use deionized water as zero calibrator.
Calibration mode Linear regression
Calibration replicate Duplicate recommended
Calibration interval Each lot

LIMITS AND RANGES

MEASURING RANGE

200-14000 U/L (3.34-234 µkat/L)

Determine samples having higher activities via the rerun function. Dilution of samples via the rerun function is a 1:2 dilution. Results from samples diluted using the rerun function are automatically multiplied by a factor of 2.

Lower limits of measurement

Lower detection limit of the test:

200 U/L (3.34 µkat/L)

The lower detection limit represents the lowest measurable analyte level that can be distinguished from zero. It is calculated as the value lying 3 standard deviations above that of a zero sample (zero sample + 3 SD, repeatability, n = 21).

SPECIFIC PERFORMANCE DATA

Representative performance data on the 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 (n = 21) and intermediate precision (1 aliquot per run, 1 run per day, 21 days). The following results were obtained:

Repeatability Intermediate Precision
Sample Mean CV Mean CV
U/L µkat/L % U/L µkat/L %
Human serum 6374 106 0.5 6675 111 1.4
Precinorm U 6263 105 0.6 6213 104 1.1
Precipath U 6015 100 0.6 5964 100 0.9

METHOD COMPARISON

CHE values for human serum samples obtained on a COBAS INTEGRA 800 analyzer using the Roche CHE2 reagent (y) were compared with those determined using Roche CHE reagent on the same analyzer (x).

Sample size (n) = 51

The sample activities were between 1192 U/L and 14411 U/L (19.9-241 µkat/L).

Passing/Bablok12 Linear regression
y = 0.970x + 128 y = 0.965x + 153
t = 0.967 r = 0.999
SD (md95) = 125 Sy.x = 37.1