[Evaluation of blood cell morphology with the RBC Advanced Application: Which cut-offs are most needed for which specific abnormalities?]

The detection of erythrocyte morphological abnormalities is a valuable and sometimes overlooked element in the diagnostic management of anemias. The aim of this article is to evaluate the clinical performance of the different detection thresholds tested by our laboratory using the Cellavision RBC Advanced module, after manual reclassification by an experienced operator, and comparing them to the guidelines by the ICSH (International Council for Standardization in Haematology). We arbitrarily set thresholds at 1% for "critical" abnormalities (tear drop cells, target cells, schizocytes and spherocytes) except for sickle cells (threshold set at 0.01%). Our data show excellent sensitivity of 100% for the cut-offs defined by the investigation for tear drop cells and sickle cells, but low specificity for detection of associated clinical pathology compared with ICSH cut-offs, varying from 4% for teardrop cells (detection of myelofibrosis), 26% for target cells (detection of martial deficiency) to 55% for schizyocytes (presence of hemolytic anemia). Our results show a better specificity of the thresholds established by ICSH than our studied thresholds for the detection of the pathologies of concern, suggesting a better clinical relevance.