Study Of Two Important Quality Indicators For Clinical Labortories:Critical Values And Turnaround Time In China

ObjectiveCritical values and turnaround time (TAT) are two important quality indicators in post-analytical process of clinical laboratories. The satisfaction of clinicians and patients as well as the safety of patients are directly influenced by those two indicators. We conducted a national cross-sectional survey on the status of the reporting of critical values and the monitoring of TAT, to provide some suggestions on routine monitoring of those two quality indicators based on the data of our survey, use them to clinical laboratories of China, and finally get the goal of quality improvement.MethodsTwo separate surveys were performed both for critical values and TAT. All of the clinical laboratories participating in the external quality assessment (EQA) programs of routine clinical biochemistry, biomarkers of myocardial injury, N terminal pro brain natriuretic peptide, blood gas, whole blood cell count and coagulation testing organized by National Center for Clinical Laboratories (NCCL) were enrolled in our study. The number of laboratories participated in the survey on critical values of clinical biochemistry, blood gas and hematology testing were1299,598and1238, respectively. And1307,598and1250for the survey of TAT, respectively. Radom sampling design was used applied in the second survey. Total600hospitals, including90tertiary hospitals and510second-class hospitals, from different areas of China were sampled.Three were three different ways to submit the required information, via the web-based EQA system, E-mails or regular mails. Both of the questionnaires were divided into two parts. The first part was on the general information of hospitals as well as the development and operation of critical values reporting procedure or the monitoring of TAT. Participants were asked questions about the selection of critical items, the sources of critical limits, the upper and lower limits and the rate of critical values in the second part of critical values survey. The medians and means of TAT for routine and emergency testing were required in the second part of TAT questionnaire. Time for the survey of critical values and TAT were2months and1week, respectively. All collected data were analyzed by the special statistical software designed by NCCL and developed by Clinet Corp. What’s more, SPSS were used to perform the peer comparison.ResultsThe return rate of the first survey for critical values on clinical biochemistry, blood gas and hematology testing were46.11%、41.14%and39.42%, respectively, among which tertiary hospitals accounted for80%of participants. The return rate for the second survey was!9%, and second-class hospitals were the majority. No significant difference of repeat testing, staff training, people and ways to report and to deal with the repetitive critical values between those two surveys was found. Besides, most laboratories in surveys suggested they set different critical limits for children and adults. The critical items chosen most frequently were potassium, glucose, sodium, calcium, pH, pCO2, pO2, WBC, Hb, PT, APTT and Fbg. The items of which the critical values occurring mostly were potassium, blood gas and creatinine for clinical biochemistry, pCO2for blood gas and WBC, Hb and PT for hematology testing. Although the total critical limits were not significantly different among in-patients, out-patients and emergency department, data of inter-laboratory varied vastly. The medians of critical limits for potassium, sodium, calcium and glucose were not significantly different from the results of the national survey conducted by Gerald Kost.The return rate for the second survey on TAT on clinical biochemistry, blood gas and hematology were36.65%,38.13%and35.92%, respectively, and17.5%for the second survey. The distribution of participants’demographic information of the survey on TAT was the same as the survey on critical values. No significant difference of the ways of ordering, results reporting, transportation and the staff responsible for sampling in emergency room between two surveys was found. In the first survey on clinical chemistry, TAT medians for routine potassium, sodium, chlorine, calcium and blood glucose were between130to140minutes, while TAT for myocardial hemoglobin and troponin closed to100minutes and121for CK-MB, and TAT for all of other items were150to170minutes. STAT TAT medians were around30minutes. TAT for potassium, sodium, chloride, calcium and glucose in the second survey were kind of smaller than the first one. However, for myocardial biomarkers, the STAT TATs were10-13minutes longer than the first one. Over97.5%of hospital’s TATs for blood gas were less than60minutes. For hematology testing, the median of TAT for routine WBC testing were42minutes and20minutes for STAT, but the results of other three items were not so satisfying. Besides, there was huge difference among laboratories. Shift was found in one-week TAT for routine testing, which was the TAT in workday were higher than those in weekends. Nevertheless, no such kind of shift was found in STAT.ConclusionThe status of critical values reporting and monitoring of TAT was unsatisfying. Remarkable inter-laboratory difference in the development and implement of critical values reporting procedure were found. Besides, some results of STAT TAT cannot meet the requirement of30minutes and the same thing happened for some routine clinical biochemistry of which the TAT exceeded6hours. In a word, laboratories should communicate positively with clinicians and get consensus on the critical analytes and limits as well as the TAT goals. Besides, clinical laboratories will hope to improve their quality by participating in the EQA programs of critical values reporting and TAT organized by NCCL.