Performance evaluation of a novel reticulocyte identification method that uses metachromatic nucleic acid staining based on a crossover analysis of emission DNA/RNA light (RNP Determination (TM)) in hematology analyzer Celltac G

Introduction Assessing the percentage of reticulocytes (%Retic) is useful for diagnosing and treating blood diseases that present with anaemia. The Celltac G+(TM) hematology analyzer (HA) uses a novel reticulocyte identification method that involves metachromatic nucleic acid staining with acridine orange and crossover analysis of emission light of DNA/RNA (determination of red cells, nucleic acid-containing cells, and platelets, RNP Determination (TM)). The red and green fluorescence generated by stained single-stranded RNA and double-stranded DNA express immaturity and morphological abnormality of erythrocytes by detecting erythrocyte RNA and DNA content. Methods The basic performance of the test automated analyzer (TAA) Celltac G+ was evaluated and compared with the flow cytometry reference method and the comparative automated analyzer (CAA) XN-1000/2000 (TM). In addition, its precision, limit of quantity (LoQ), linearity, analytical measurement interval (AMI), accuracy, and comparability and the effects of interfering substances were evaluated. Results Evaluation of %Retic by the TAA demonstrated good precision and linearity. The AMI was confirmed from 0.02 to 8.23, and the LoQ in %Retic as the coefficient of variation within an 11% limit (SD, within a 0.01 limit) was 0.14. TAA correlated well with the reference method and routine HA (CAA). Some deviations were found between TAA and CAA in DNA measurements of erythrocytes from abnormal samples. Conclusion Celltac G+ uses a novel measurement principle and can assess erythrocyte immaturity independent of DNA contents. It represents a new HA that provides novel, useful information on immaturity and morphological abnormality of erythrocytes.