Establishment and Evaluation of an Internal Quality Control Method for ESR Relays

This study establish and evaluate an internal quality control system for erythrocyte sedimentation rate (ESR) by a "relay" mode based on samples from relevant patients.

The method for establishing a new internal quality control system for ESR by a "relay" mode based on patient's samples was executed from February 2021 to July 2021. In this paper, a total of 219 outpatients were recruited for ESR determination, and their blood samples were stored at 4 °C or room temperature for 24 h. Subsequently, the samples were re-measured for ESR, and the re-measured values were compared with the initial values. The patient samples (15±1mm/h and 50±3mm/h) were selected after the TEST1 ESR analyzer was calibrated, and were stored overnight at 4 °C and measured again the following day. The percentage deviation was determined and entered into the quality control management module for internal quality control. Next, we analyzed the median distribution trend of the patients' ESR values measured by our laboratory every day over five months, as well as the external quality assessment (EQA) results for ESR obtained from the National Center for Clinical Laboratories (NCCL).

The ESR of the room temperature samples after 24 h of storage had significantly decreased (P=0.001), while there was no noticeable difference for those stored at 4 °C (P=0.197). Results of the internal quality control in March were satisfactory, and there was no significant deviation in the median ESR relay results within five months. Besides, the EQA results for the ESR data obtained from NCCL were excellent.

As a precise and practical new method, the ESR relay internal quality control method can be used to scientifically determine the stability and accuracy of the TEST1 ESR analyzer.