Initial results of Central European Immunophenotyping Quality Control Program (CEQUAL).

The new Quality Control Program in Immunophenotyping for Central Europe (CEQUAL) was created in 1993. Its first formal send-around proficiency exercise, consisting of a stained stabilised preparation of leukocytes, took place in November 1993. Forty-one laboratories from Slovakia, Poland, Hungary, and the Czech Republic participated. Eighty-three percent of member laboratories returned results and list mode files. The results for each cell population were evaluated for central tendencies, variability, and overall distribution patterns. Extreme outliers were identified and list mode files reviewed for clues to the aberrerant values. When found these reasons were communicated back to member labs. When extreme outlier values were removed, all coefficient of variations (CVs) for lymphocyte populations were below 10%, except for NK cells, which had a CV of 14.8%. In future send-arounds, unstained and pathologic specimens will be used. This CEQUAL program is the first to function on such a broad international basis.