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57
| 3 | 2009
Klinisk Biokemi i Norden
bias for the medium level was -4,9% and significantly
below -4,0%. This bias, valid for HbA1c concen-
trations between 5.7 and 9.7 HbA1c%, is clinically
interesting and includes two thirds of all results in the
hospital evaluation. When Afinion is used in primary
health care it is expected that about 90% of the results
will fall within this concentration interval. This jus-
tifies the assessment that Afinion did not fulfil the
SKUP quality goal for bias.
Total error
According to the quality goals set by SKUP, 95%
of the B—HbA1c results of Afinion should not
deviate more than ±10% from the corresponding
Comparison Method results. The Afinion results
with venous samples measured in the hospital labo-
ratory did not fulfil the quality goal for total error as
only 92% were inside the limits. The Afinion results
with capillary samples measured at the primary care
centres did not fulfil the quality goal either as only
as 93% were inside the limits. However, many of the
measurements outside the 10% limits were very close
to the limits.
User-friendliness
The evaluators had the general opinion that Afinion
was user-friendly. They liked the system and thought
it was easy to handle. The most important negative
opinion concerns the high frequency of error codes.
The other negative opinion concerns the internal
quality control materials which were very viscous and
difficult to mix and handle.
The error code frequency was 8%. The probable
explanation was that the detection systems causing
the error codes were too sensitive. Regardless of
cause, the frequency of error codes was assessed as
too high.
Conclusion
Afinion was easy to handle. The precision of
Afinion was good and fulfilled the quality goal.
However, the bias for the medium level was −4,9%
and too many results were outside the total error
limits. Afinion did therefore not fulfil all analyti-
cal quality goals. The error code frequency was
also too high.
The negative bias found in the evaluation has after
the evaluation been confirmed in the EQUALIS and
NOKLUS EQA-schemes.
The complete report, with comments and addi-
tional information from Axis-Shield, is available at
www.skup.nu
Picture of Afinion AS 100 Analyzer
Difference diagram, venous samples
in the hospital laboratory
The deviations of the Afinion results from the Comparison
Method results are shown for 99 venous patient samples.
Stippled lines represent the tolerance limits ±10%.
Results are shown with different symbols depending on
used lot of Test Cartridges: lot 10128762 = blue squares, lot
10128335 = green circles and lot 10127761 = red triangles.
Three results which were error codes on Afinion are shown
below −2,0 in the diagram.
In addition to the error code results there were eight results
outside the tolerance limits.
Five results were below the low limit and three results were
above the high limit.
