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Evaluation of Sysmex R1000 Automated Reticulocyte Analyser

Shirley Mitchell LewisBrendan J. GarveyR. M. RowanG. CumminsT. McLaren

出版	Department of Health, NHS Procurement Directorate, 1990
URL	http://books.google.com.hk/books?id=CDI8vwEACAAJ&hl=&source=gbs_api

註釋Reticulocyte counts have been an established diagnostic test for many years, but their use and value have been limited by the laborious procedure and imprecision of measurement. The advent of automated reticulocyte counting overcomes these limitations and provides a potentially important advance in haematology practice. The R1000 is a dedicated reticulocyte counting system based on fluorescent flow cytometry. Fluorescence is activated in reticulocytes which are stained with auramine O by argon-laser light at 488 nm. Intensity of fluorescence is proportional to RNA concentration, and other fluorescing particles (e.g. platelets) are discriminated by size. This evaluation has been carried out in two centres using the ICSH (1984) protocol for evaluation of automated blood cell counters. It includes information on initial purchase price, reagent and maintenance cost, workload and clinical usefulness. Performance has been assessed with statistical analysis of linearity of response, precision and accuracy (by comparison with a microscopic reference method). Microbiological safety assessment is reported and the manufacturer's specification of electrical safety is included. Analysis of variance showed intrabatch and interbatch CVs of 4-5%. Precision study on 10 replicate measurements gave a CV of 15% with reticulocytopenias (i.e. R = 0.3%; 7 x 10[9]/1), 7% with reticulocytes in the normal range (i.e. R = 1%, 27 x 10[9]/1) and CV less than 4% with reticulocytosis (i.e. R = 5%; 165 x 10[9]/1). Comparability studies were carried out on 65 specimen collected for routine tests, instrument counts being compared with those obtained by reference microscopy. Differences between paired tests were not significant but there was a mean bias of +12.5% for absolute counts and -3.7% when expressed fractionally (R%). There was negligible between - sample carry over. Heinz bodies and HB H did not influence counts. Malaria parasites were fluorescent and therefore intracellular parasites could not be distinguished from reticulocyte although extracellular parasites were excluded by size discrimination. Time lapse studies showed that specimens remain stable at 4 degrees C for 72 hours, but that reticulocytes begin to fall progressively after 6 hours at room temperature. Reticulocytes are classified by the intensity of fluorescence into three grades which correspond to Heilmeyer's grades I, II-III and IV and which broadly represent their age and rate of entry into circulation. Throughput time was approximately 60 samples per hour.(ABSTRACT TRUNCATED AT 400 WORDS).