Objective To explore the value of using LISsystem sample time flow function to guarantee the inspection quality of time limited samples.Methods The urine routine,blood ammonia and blood gas analysis collected by inpatient department of department of clinical laboratory in People′s Hospital of Jilin City from July to December 2017 and from January to June 2017 were selected as time-limited samples,and there were 25 679,912,5117 cases,and 24 313,867,4895 cases.From January to June 2017,the routine standard operation process was used to detect the time limited samples while from July to December 2017,the setting of pre-warning time was added on the basis of routine standard operation process:the pre-warning time of urine routine was 90 min,blood ammonia was 30 min,and blood gas analysis was 10 min.The coincidence rate,median and 90%digits of turnaround time (TAT)for time limited samples in different time periods were compared.Results The coincidence rates of TAT in urine routine,blood ammonia and blood gas analysis from July to December 2017 was 98.7%,97.1%and 98.3%respectively,which was significantly higher than that from January to June 2017 (90.5%,80.5%and 88.6%)respectively (P<0.05).From January to June 2017,the median and 90%digits of TAT in urine was 32.6,62.5 min rspectivley,blood ammonia was 20.6,45.8 min,and blood gas analysis was 20.6,27.8 min,which were shorter than those from January to June 2017 (48.5,88.6 min;32.6,55.7 min;23.8,29.1 min)(P<0.05).Conclusion The sample time flow function of the LISsystem can guarantee the time detection requirement and detection quality of time limited samples.