Peykan check, a simple continuous quality control method for hematology analyzers

A simple inexpensive con!nuous quality control method, by means of eight basic blood coun!ng parameters, obtained from automated hematology analyzers, using pa!ent samples, is described. a few samples with low, normal and high values were selected and introduced to the instrument early in the morning as the first count, the results of which are plo#ed on the appropriate chart as dots. the same samples were again given to the instrument at noon and the results were plo#ed on the same chart as the arrow heads. an arrow is then drawn from each pair of consecu!ve counts. the same procedure is repeated every 6 hours, using a newly selected set of samples, and the last sample which is selected in late evening on each day, is introduced to the instrument on the next morning. hence pa!ent samples are run at the beginning and the end of three daily work shi$s. an explana!on is given to use the direc!on of the arrows as the main factor to assess the quality of the instrument performance. this method can be easily applied to any hematological laboratory and can simply be performed even by laboratory technicians