In 1991, the external quality assessment in hematology was done two times for the members' laboratories. In this year the quality assessment for the coagulation tests(PT, APTT) were included since the last trial of 1985.
The numbers of participants was 227 in the first trial, 252 in the second trial and the reply rates were 7.58%, 87.7% respectively. the coagulation tests(PT, APTT) were performed for 182 laboratories in the first and 170 laboratories in the
second
trial
and their reply rates were 72.5%, 85.3% respectively.
Of 252 members' laboratories, 195(77.4%) laboratories had automated blood cell counters. Also 14 different types of coagulation analyzers as well as 9 and 16 different types of PT & APTT reagents we found. The automation rates were fond to be
73.5%
in
the PT and 80.5% in the APTT test. The Royal College of Patologists of Australasia Hematology Quality Assurance Program was taken to make CBC specimens. The lyophilized plasma for the PT & APTT tests were kindly provided by Korea Standards
Research
Institute. The excellent CV value were noted in automatic counting of WBC and platelet, reflecting the stability of quality control materials.
In the WBC differential counts, relatively high concordance rate was found in the first trial(slght monocytosis) but in the second trial(ALL), 37.7% of the members laboratories had failed to note lymphoblast. In the answers of RBC size
examinations,
about 1/2 and 1/4 among entire answers were inaccurately observed in each trials respectively.
For the PT & APTT tests, the first lyophilized plasma was known to have normal PT and prolonged APTT values. The answers were consistent with the reference value in 97.3% (PT) and 71.2% (APTT) of entire answers respectively. In the case of second
lyophilized plasma, normal PT and upper limit of normal APTT values were measured from our data of subcommittee. Although normal PT value was found in 94.8% of entire answers, only 32.4% of the answers were consistent with the data of
subcommittee
unexpectively. The exact cause is not clear, but it cold be assumed that the differences of reagents and analyzers as well as the way to make normal range were thought to contribute to this puzzling outcome. So it must be necessary to have
several
reliable reference laboratories according to this puzzling outcome. So it must be necessary to have several reliable reference laboratories according to the each type of the reagents and analyzers as well as providing more qualified QC materials
to
obtain more advanced achievement of quality control in the field of coagulation tests.
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