Upsala J Med Sci 91:221, 1986 

Experiences from a Laboratory Evaluation of a Solid Phase 
Analytical System 

Kristoffer Hellsing, Catarina Bernet and Annika Lindback 
Department of Clinical Chemistry, University Hospital, Uppsala, Sweden 

Glucochek I1 from Medistron, UK, was kindly supplied by Orion 
Diagnostica, Sweden. This reflectometer was especially construc- 
ted in order to make serial analyses possible. The test strip BG 
was kindly supplied by Boehringer Mannheim Scandinavia. The 
EDTA-blood samples used had been sent to the laboratory for rou- 
tine glucose determinations. 

Imprecision: Within-series ( 2 0  samples) imprecision values 
were in the order of 2-3 CV% within the range 5 - 15 mmol/l, but 
for samples with low glucose content ( 1 . 6  and 3.8 mmol/l) the 
imprecision was 6 . 6  and 9.7 CV% resp. In order to obtain these 
values a familiarization period for the technician was necessary. 

Comparison: When 2 0  samples ( 3 - 1 2  mmol/l) were compared with 
two of our routine methods (Glucose dehydrogenase method on Grei- 
ner G-300 and Glucose analyser from YSI) the tested method gave a 
reasonable correlation but showed 2 0 %  higher values. 

Time factors: The first incubation time (blood on the rea- 
gent strip, varied 1 0 - 3 0 0  s )  is important. After the recommended 
time, 6 0  s ,  there is still an increase of colour development. 
After an incubation time of about 1 5 0  s a plateau is reached. The 
second incubation time (after blood has been wiped off, varied 
10-330s) is not critical. At 6 0  s the reading is on a slowly de- 
creasing slope which reaches a minimum after 2 - 3  min. The changes 
are, however, s o  small that even big misreadings are unimportant. 

Influence of hematocrit: It has been claimed (Kutter; 
Schnelltest in der Klinischen Diagnostik, 1983, p. 5 5 )  that the 
result is inversely dependent of the hematocrit. We could confirm 
this observation. The decrease was, however, of the same size 
even using the reference method (Glucose analyser). Thus, the 
decrease is not dependent on the reagent strip but rather on the 
blood as such. 

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