Abstract:

Objective To analyze the role of the re-examination rule for platelet（PLT）count based on MicroR，mean corpuscular volume（MCV）and red blood cell distribution width（RDW）developed by fully automatic hematology analyzer. Methods Blood samples from 526 outpatients at the First Affiliated Hospital of Zhejiang University School of Medicine（experimental group）and 68 healthy subjects（control group）were collected from June 2023 to March 2024. Additionally，161 samples from patients at the First Affiliated Hospital of Zhejiang University School of Medicine in the same period were collected as re-examination positive verification samples for the rule，and 70 samples from healthy subjects were collected as re-examination negative verification samples. The XN-20 hematology analyzer was used in PLT-F mode to determine various blood routine indicators. The differences in the determination results between the 2 groups were compared. Receiver operating characteristic（ROC）curve was used to evaluate the efficacy of MCV，RDW and MicroR in guiding PLT re-examination. The MicroR re-examination rule was verified using the re-examination verification samples. Results There was statistical significance in white blood cell count，hemoglobin（Hb），MCV，RDW，PLT count and MicroR between experimental group and control group（P<0.05），while there was no statistical significance in red blood cell count，mean PLT volume and PLT-larger cell ratio（P>0.05）. The areas under curves for MicroR，MCV and RDW in guiding PLT count re-examination were 0.716，0.720 and 0.474，respectively. The sensitivities were 80.0%，72.9% and 16.0%，respectively，and the specificities were 52.7%，62.1% and 72.4%，respectively. When MicroR≥16.5%，the true positive rate，true negative rate，false positive rate and false negative rate of PLT re-examination were 93%，52%，48% and 7%，respectively. Conclusions The ability of MicroR to guide PLT count re-examination is comparable to that of MCV but significantly better than that of RDW. It is recommended that clinical laboratories set the MicroR≥16.5% re-examination rule in daily work to replace the MCV<75 fL and RDW>22% rules.

Key words: Platelet count, Re-examination, Hematology analyzer, Fluorescent platelet channel