Correction of Pseudoreticulocytosis in Leukocytosis Samples Using the Sysmex XE-2100 Analyzer Depends on the Type and Number of White Blood Cells.
10.3343/alm.2012.32.6.392
- Author:
Ahhyun KIM
1
;
Joonhong PARK
;
Myungshin KIM
;
Jihyang LIM
;
Eun Jee OH
;
Yonggoo KIM
;
Yeon Joon PARK
;
Kyungja HAN
Author Information
1. Department of Laboratory Medicine, The Catholic University of Korea College of Medicine, Seoul, Korea. hankja@catholic.ac.kr
- Publication Type:Original Article
- Keywords:
Reticulocytes;
Leukocytosis;
Reticulocyte count
- From:Annals of Laboratory Medicine
2012;32(6):392-398
- CountryRepublic of Korea
- Language:English
-
Abstract:
BACKGROUND: The reticulocyte count is a good marker of erythropoietic activity of the bone marrow. In the mid-1990s, automated flow cytometric analysis replaced microscopy for the quantification of reticulocytes. Leukocytosis cases with an erroneously high reticulocyte count and a high immature reticulocyte fraction (IRF) have been reported. In this study, we analyzed reticulocyte counts in leukocytosis samples, in an effort to identify a correction method. METHODS: The study comprised of 21 samples from 16 leukocytosis patients. Results of reticulocyte analyses obtained using a XE-2100 hematology analyzer (Sysmex, Japan) were compared with those obtained using the supravital staining technique, which is a reference method. If the samples showed erroneously high reticulocyte counts and IRF, they were reanalyzed after serial dilution with isotonic solution. RESULTS: Five samples from 4 patients showed erroneously elevated reticulocyte counts and/or IRF on the XE-2100 analyzer. They displayed abnormal reticulocyte scattergrams, with 4 of 5 cases indicated by a flag. The white blood cell (WBC) fractions overlapped with the reticulocyte regions, especially with the IRF. Diagnoses and blast counts were variable when such errors occurred; WBC counts varied from 218.19x10(9)/L to 725.14x10(9)/L. The errors were corrected by simple dilution with isotonic solution. However, the corrective WBC counts differed according to individual cases. CONCLUSIONS: When leukocytosis samples exhibit an abnormal reticulocyte scattergram with a flag, or an abnormally high IRF, we recommend the dilution of the sample with isotonic solution to a WBC count of about 100.00x10(9)/L, followed by reanalysis of the reticulocyte count and reticulocyte scattergram.
