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| 3 | 2004
Klinisk Biokemi i Norden
27
Hemo_Control haemoglobin measuring system
(Hemo_Control) is intended for determination of
the haemoglobin concentration in human blood.
Hemo_Control consists of an absorption photome-
ter and microcuvettes that contain dried reagents.
In the cuvette, haemoglobin is converted to azide
methaemoglobin, a coloured product that is measu-
red bichromatically in the photometer. The sample
volume is 10 µL. The sample can be drawn directly
into the Hemo_Control Microcuvette from a capil-
lary puncture. The cuvette is read directly in the
Hemo_Control Photometer. The measuring range is
0 — 256 g/L (0.00 — 15.89 mmol/L).
Hemo_Control is manufactured by EKF-diagnostic
GmbH in Germany. The evaluation was ordered by
MEDimport AS in Norway. The first part of the evalu-
ation was performed under standardised and optimal
conditions by experienced laboratory technologists
in a hospital laboratory in Sweden. The second part
was performed under real life conditions by staff at
two primary care centres in Norway. The analytical
quality goal derived from biological variation was set
to allow a total error of up to ±5 %.
Results
The within-series precision with venous EDTA samp-
les in the hospital laboratory was good. The CV was
around 1 %. When the imprecision was measured
between days the CV figures did not increase. There
was a small, but negligible, negative bias relative to
the Comparison Method on Coulter LH 750. The total
error was less than ±5 %. The results achieved in the
hospital laboratory fulfil the analytical quality goal.
The precision with venous samples at the primary
care centres was also good. The CV was 0.7 and 1.5 %
respectively. There was a positive bias, but negligi-
ble small, relative to the Comparison Method. These
results also fulfil the analytical quality goal with a
total error of less than ±5 %.
Using capillary samples taken in the finger the
imprecision was higher, as expected. At Centre B
the imprecision was acceptable, with CV 2.8 %. At
Centre A the imprecision was too high, with CV 5.5 %.
The quality goal was therefore not attained with
capillary samples. It is a complicating fact that the
haemoglobin concentration in capillary blood is not
representative for the haemoglobin concentrations
in venous blood. These pre-analytical sources of
error are not only valid for Hemo_Control, but for
all instruments using capillary samples for mea-
suring B-Haemoglobin.
Practical points of view
All personnel involved in the evaluation summari-
sed their opinion about the Hemo_Control system as
being quick and easy to use. They also thought the
instrument was small and neat.
Conclusion
Hemo_Control showed, when using venous samples,
good precision and only small deviations from the
results of the Comparison Method. The bias was
small and negligible. The total error was less than
±5%. The quality goal is attainedwith venous samples.
The quality goal was not attained with capillary sam-
ples, mainly due to non-representative haemoglobin
concentrations in capillary puncture blood and to
poor precision. Acceptable precision can be obtained
with skilful sample collection, but the non-repre-
sentative concentrations appear impossible to avoid.
These pre-analytical sources of error with capillary
samples are valid not only for Hemo_Control, but for
all instruments measuring haemoglobin.
Hemo_Control is quick and easy to use and well
suited for the Primary health care.
The complete Hemo_Control evaluation report
is available at www.SKUP.nu
Hemo_Control haemoglobin measuring system
Grete Monsen and Arne Mårtensson, SKUP
(grete.monsen@isf.uib.no, arne.martensson@equalis.se)
Summary of an evaluation organised by SKUP
Report SKUP/2004/29
