CK-MB - the MB isoenzyme of creatine kinase

Catalog Number: 05894808160

INTENDED USE

Immunoassay for the in vitro quantitative determination of the MB isoenzyme of creatine kinase in human serum and plasma.

Measurements of the MB isoenzyme of creatinine kinase are used as an aid in the diagnosis of myocardial infarction.

The electrochemiluminescence immunoassay “ECLIA” is intended for use on Elecsys and cobas e immunoassay analyzers.

STORAGE AND STABILITY

Stability:
unopened at 2-8 °C up to the stated expiration date
after opening at 2-8 °C 12 weeks
on the analyzers 8 weeks

Store at 2-8 °C.

Do not freeze.

Store the Elecsys reagent kit upright in order to ensure complete availability of the microparticles during automatic mixing prior to use.

CALIBRATION

Traceability: The Elecsys CK-MB assay is traceable to the Abbott IMx CK-MB assay and linearized using human recombinant CK-MB4 from Seradyn.

Every Elecsys reagent set has a barcoded label containing specific information for calibration of the particular reagent lot. The predefined master curve is adapted to the analyzer using the relevant CalSet.

Calibration frequency: Calibration must be performed once per reagent lot using fresh reagent (i.e. not more than 24 hours since the reagent kit was registered on the analyzer). Renewed calibration is recommended as follows:

LIMITS AND RANGES

Measuring range

1-300 ng/mL (defined by the Limit of Quantitation and the maximum of the master curve). Values below

the Limit of Quantitation are reported as < 1 ng/mL. Values above the measuring range are reported as

> 300 ng/mL (or up to 600 ng/mL for 2-fold diluted samples).

Lower limits of measurement

Limit of Blank (LoB), Limit of Detection (LoD) and Limit of Quantitation (LoQ)

Limit of Blank = 0.1 ng/mL

Limit of Detection = 0.3 ng/mL

Limit of Quantitation = 1 ng/mL with an intermediate precision coefficient of variation of ≤ 20 %.

The Limit of Blank, Limit of Detection and Limit of Quantitation were determined in accordance with the CLSI (Clinical and Laboratory Standards Institute) EP17-A requirements.

The Limit of Blank is the 95th percentile value from n ≥ 60 measurements of analyte-free samples over several independent series. The Limit of Blank corresponds to the concentration below which analyte-free samples are found with a probability of 95 %.

The Limit of Detection is determined based on the Limit of Blank and the standard deviation of low concentration samples. The Limit of Detection corresponds to the lowest analyte concentration which can be detected (value above the Limit of Blank with a probability of 95 %).

The Limit of Quantitation is defined as the lowest amount of analyte that can be reproducibly measured with an intermediate precision coefficient of variation of ≤ 20 %.

SPECIFIC PERFORMANCE DATA

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

PRECISION

Precision was determined using Elecsys reagents, samples and controls in a protocol (EP5-A2) of the CLSI (Clinical and Laboratory Standards Institute): 2 runs per day in duplication each for 21 days (n = 84). The following results were obtained:

Elecsys 2010 and cobas e 411 analyzers
Repeatability Intermediate precision
Sample Mean SD CV SD CV
ng/mL ng/mL % ng/mL %
Human serum 1 5.27 0.069 1.3 0.107 2.0
Human serum 2 28.4 0.398 1.4 0.679 2.4
Human serum 3 91.2 1.13 1.2 2.34 2.6
Human serum 4 297 3.99 1.3 5.99 2.0
PreciControl CARD1 4.25 0.059 1.4 0.099 2.3
PreciControl CARD2 54.7 0.650 1.2 1.26 2.3

MODULAR ANALYTICS E170, cobas e 601 and cobas e 602 analyzers
Repeatability Intermediate precision
Sample Mean SD CV SD CV
ng/mL ng/mL % ng/mL %
Human serum 1 5.45 0.041 0.7 0.088 1.6
Human serum 2 28.6 0.333 1.2 0.610 2.1
Human serum 3 90.5 1.07 1.2 1.55 1.7
Human serum 4 296 3.06 1.0 4.73 1.6
PreciControl CARD1 4.36 0.044 1.0 0.084 1.9
PreciControl CARD2 55.6 0.401 0.7 0.830 1.5

METHOD COMPARISON

A comparison of the Elecsys CK-MB assay (y) with the Elecsys CK-MB STAT assay (x) using clinical samples gave the following correlations:

Number of samples measured: 115

The sample concentrations were between 1.00 and 300 ng/mL.

Passing/Bablok6 Linear regression
y = 1.00x - 0.005 y = 1.01x + 0.071
t = 0.985 r = 0.999

ANALYTICAL SPECIFICITY

For the monoclonal antibodies used the following cross-reactivities were found: CK-MM none, CK-BB 0.1 %.