Objective To optimize the statistical caliber of the total number of outpatient visits.Methods Through analyzing the characteristics of three ways of billing for COVID-19 nucleic acid testing in outpatient and emergency departments of hospitals, namely self-service machine, mobile APP and doctor billing, the module of "accompanying COVID-19 testing" was added to the outpatient and emergency prescription system, the value of special labeled fields was added, the screening logic and calculation formula were clarified, information was obtained from HIS system and program statements were edited. Accurate statistics of the number of COVID-19 nucleic acid tests was achieved, as well as the total number of outpatient visits after eliminating the number of nucleic acid tests.Results The statistical module based on process combing and information program design of the HIS system can efficiently and accurately achieve the latest statistical caliber requirements and reflect the actual medical visits more accurately.Conclusion It can strengthen the objectivity of data comparison in different periods and provide more valuable data for hospital outpatient operation and management to accurately extract the nucleic acid test persontimes and calculate the total out-patient visits after the exclusion.