Performance evaluation of the Sysmex haematology XN modular system
- 1Department of Haematology, University College London Hospital, London, UK
- 2Department of Haematology, The Doctors Laboratory, London, UK
- Correspondence to Carol Briggs, Department of Haematology, University College London Hospital, Haematology Evaluations, 5th Floor, 60 Whitfield Street, London W1T 4EU, UK;
- Accepted 18 June 2012
- Published Online First 31 July 2012
Background The Sysmex XN haematology instrument performs automatic reflex testing, depending on sample results. A nucleated red blood cell (NRBC) count is provided on all samples. The instrument has a smaller footprint (34%) than previous Sysmex XE analysers.
Methods An evaluation comparing all results to the Sysmex XE-2100 and manual microscopic differential and morphology (n=390) was performed followed by a workflow study of 1000 samples to compare speed of operation and number of blood films reviews required from both systems.
Results The new features on the instrument are: (1) white cell and NRBC channel, all samples include the NRBC count; (2) white cell precursor channel: false positive flags for blasts, abnormal lymphocytes and atypical lymphocytes are reduced significantly without a statistical increase of false negatives; (3) low white cell count mode: suggested setting of <0.5×109/l. An extended count is more precise and provides an accurate differential. Fluorescent platelet count is performed in a dedicated channel. If the red cell or platelet size histograms are abnormal or if the platelet count is low, then a fluorescent platelet count is automatically performed. Good correlation with the XE-2100 and manual differential was found and the improved results compared to the reference flow cytometric analysis for platelet counts, especially below 30×109/l (XE-2100, R2=0.500; XN, R2=0.875).
Conclusion The XN showed reduced sample turnaround time of 10% and reduced number of blood films for examination, 49% less than the XE-2100 without loss of sensitivity with more precise and accurate results on low cell counts.