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Klinisk Biokemi i Norden · 1 2020
Figure 1.
cobas b
101 analyser with three different test discs.
Summary of an evaluation
organised by SKUP
Anne Christin Breivik, on behalf of SKUP
Cobas b 101 for measurement of CRP
Background
The
cobas b
101 system (Figure
1) is an in vitro diagnostic device
for quantitative measurement of
C-reactive protein (CRP), Hae-
moglobin A1c (HbA1c) and lipids.
The product is intended for profes-
sional use. The
cobas b
101 system
is produced by Roche Diagnostics GmbH and was
launched into the Scandinavian market April 2013.
This summary concerns the SKUP evaluation of
cobas b
101 CRP measurements in capillary whole
blood samples. The sample material for CRP mea-
surements can also be serum and venous ethylene-
diaminetetraacetic acid (EDTA), as well as lithium
heparin anticoagulated whole blood and plasma. The
measuring interval for
cobas b
101 CRP is 3,0 – 400
mg/L. The SKUP evaluation was carried out in spring
2019 at the request of Roche Diagnostics Denmark
and Roche Diagnostics Norway and in parallel with
evaluations of
cobas b
101 HbA1c and
cobas b
101
Lipid Panel.
The aim of the evaluation
The aim of the evaluation was to assess the analyti-
cal quality and user-friendliness of
cobas b
101 CRP,
both when used under optimal conditions by expe-
rienced laboratory personnel, which documents the
quality of the system under conditions as favourable
as possible for achieving good analytical quality, and
when used by intended users in primary health care,
which documents the quality of the system under
real-life conditions.
Materials and methods
Capillary whole blood samples from 106 patients
were measured on
cobas b
101 CRP by a biomedical
laboratory scientist under optimal conditions. Under
real-life conditions in each of two primary health care
centres (PHCC1 and PHCC2) capillary whole blood
samples from 55 and 50 patients, respectively, were
measured on
cobas b
101 CRP. Venous serum samples
from the same patients were analysed on a compari-
son method (CRP Vario immunoturbidimetric assay,
Architect plus c16000, Abbott). The analytical results
and user-friendliness were assessed according to pre-
set quality goals. The quality goal for precision was a
repeatability (coefficient of variation, CV) ≤10,0 %.
The quality goal for accuracy was that ≥95 % of the
results should be within the deviation limits of ±2,0
mg/L for CRP concentrations <10 mg/L and ±20,0 %
for CRP concentrations ≥10 mg/L in relation to the
comparison method. The user-friendliness was asses-
sed using a questionnaire with three given ratings;
satisfactory, intermediate and unsatisfactory, and
with the quality goal of a total rating of “satisfactory”.
Results
The CV achieved under optimal conditions
was between 2,1 and 2,6 % depending on the
concentration level. The PHCCs achieved a
CV between 1,9 and 2,7 %. All the results were
within the allowable deviation limits for accuracy
