Objective:To investigate the application of patient-based real-time quality control (PBRTQC) using exponentially weighted moving average (EWMA) method in internal quality control (IQC) procedures of thyroid function tests.Methods:The serum thyroid function test results of outpatients and inpatients in the Second Hospital of Shandong University from December 1, 2022 to April 30, 2023 were collected. Based on the PBRTQC professional intelligent software system, normality correction, parameter setting, program preparation and real-time operation of test data were carried out. The results of all patients who underwent thyroid function testing between May 1, 2023 and August 31, 2023 were used as the validation dataset. The estimated EWMA value of thyroid function test results and the cumulative coefficient of variation ( CV) over 4 months were calculated. The cumulative CV was compared with the criteria of precision quality standard (1/3TEa) and the CV of IQC. Westgard 2-2s and 1-3s rules were used for alarm setting. The early warning information of the EWMA quality control program were recorded and the potential causes of performance changes were analyzed. DxLab Mind software was used to conduct normal distribution statistics for all data, and the Kolmogorov-Smirnov test was performed on the test results. Results:The items related to serum thyroid function of the patients were all positively skewed. After data correction by Box-Cox method, the PBRTQC data of free triiodothyronine (FT3) and free thyroxine (FT4) were normally distributed, and their cumulative precisions ( CV) of EWMA within 4 months were 6.26% and 2.86%, respectively, both of which were lower than the precision quality target of 8.33%. However, the data of thyroid-stimulating hormone (TSH), thyroid peroxidase antibodies (TPOAb) and thyroglobulin antibody (TgAb) were still positive skewed after modification. The EWMA cumulative CV of TSH, TPOAb and TgAb were 13.16%, 15.31% and 16.77%, which were higher than the precision quality targets of 8.33%, 10% and 10%, respectively. The EWMA QC program can detect different out-of-control alarms, including FT4 false alarms due to sample source concentration and TSH result bias caused by changes in reagent performance. In addition, the EWMA QC program can also detect differences in FT3 results between different DXI800 fully automated chemiluminescence instrument instruments. Conclusions:The EWMA program based on PBRTQC professional intelligent software tools can monitor the patient data of the detection system in real time and continuously, dynamically identify and monitor the errors generated during the analysis process and give early warning. It can be used as a useful supplement for the daily IQC of thyroid function items, especially FT3 and FT4, and has good clinical application value.