Reducing Laboratory Turnaround Time Outliers Can Reduce Emergency Department Patient Length of Stay

Reducing Laboratory Turnaround Time Outliers Can Reduce Emergency Department Patient Length of Stay
Lorne L. Holland, MD; Linda L. Smith; Kenneth E. Blick, PhD

Sociedad Argentina de Terapia Intensiva
CAPITULO BIOQUIMICO

Abstract and Introduction
Abstract
Poor core laboratory performance that causes delays in diagnosis and treatment is an impediment to optimal patient care, particularly in high-volume patient care areas such as the emergency department (ED). To evaluate the impact of laboratory performance on patient care outcomes, we obtained data from 11 hospitals related to laboratory test turnaround time (TAT) parameters and ED patient throughput.
We observed that the average length of stay (LOS) in the ED correlated significantly with the percentage of total laboratory outliers (R2 = 0.75; P < .01) and to a lesser extent the TAT means (R2 = 0.66; P < .01). Furthermore, improvements in laboratory performance during the study were associated with concurrent decreases in ED LOS.
Although in the past, laboratories have focused on TAT means for performance assessment, our observations suggest that a more appropriate method of benchmarking might be to aggressively set clinically driven TAT targets and assess performance as the percentage of results achieving this goal.
Introduction
It has been observed that faster interventions generally are associated with better outcomes for patients.[1,2] Moreover, the emergency department (ED) length of stay (LOS) correlates with additional inpatient LOS,[3,4] suggesting initial delays in diagnosis and management in the ED continue to have repercussions even after the patient has been admitted. Because 60% to 70% of the objective information on the patient\'s chart is laboratory information, it follows that delays in reporting laboratory results would cause a concomitant delay in the diagnosis and management of patients.
The influence of rapidly available laboratory data on the efficient diagnosis and management of patients in the ED has been reported for satellite laboratory and point-of-care testing.[5-7] However, these studies focused only on improvements in the ED LOS owing to the addition of ED point-of-care testing with no attention given to potential effects of core laboratory testing on the ED LOS. Therefore, to study the relationship of core laboratory testing perfor-mance and ED LOS, we measured turnaround time (TAT) means and percentages of TAT outliers in 11 hospitals for tests commonly used by the ED, including CBC count, electrolytes, cardiac markers, and urinalysis. Previous studies had suggested that TAT means and frequency of outliers were useful tools for assessment of laboratory perfor-mance[8,9]; however, neither of these reports included patient outcome data. Hence, the focus of this study was to address the issues of the direct impact of core laboratory perfor-mance on ED LOS and which laboratory TAT metric is the best indicator in terms of ED LOS.
Materials and Methods
Laboratory TAT Data
We measured the laboratory received to verified TAT means and TAT outlier percentages (OPs) in 11 community hospitals from November 2003 through July 2004. We measured TATs for basic and comprehensive metabolic panels, troponin I, CBC count, and urinalysis. Outliers were defined as more than 30 minutes for a CBC count, more than 40 minutes for chemistry mea-surements, more than 60 minutes for troponin I measurement, and more than 30 minutes for a urinalysis. We also measured the ED patient lengths of stay in these hospitals. All 11 hospitals used the same chemistry analyzer (Dade Dimension RxL, Dade, Deerfield, IL) for chemistry and cardiac testing; in hematology, different instruments were used (Abbott Cell-DYN, Abbott, Abbott Park, IL; Coulter, Beckman Coulter, Brea, CA); and for urinalysis, the Roche Criterion (Roche, Indianapolis, IN) strip reader was used.
Database Creation
For information technology, all hospitals included used the Meditech Version 4.9.1 (Meditech, Westwood, MA) for obtaining laboratory TAT and ED patient LOS data. For database processing, raw data from the Meditech hospital information system were downloaded as text files into Microsoft Excel (Microsoft, Redmond, WA) with subsequent transfer of these data into a Microsoft Access database for analysis. Before transfer to the Access database, data from the different hospitals were standardized by removing obvious inaccuracies such as zero values for TAT and TAT results that were clearly cancellations or add-on tests.
Calculations and Statistics
Final tabulations of TAT outlier percentages and TAT means were performed in Access with report generation, including charts and graphs, created in Excel. Statistical calculations were performed using Microsoft Excel.
Materials and Methods
Laboratory TAT Data
We measured the laboratory received to verified TAT means and TAT outlier percentages (OPs) in 11 community hospitals from November 2003 through July 2004. We measured TATs for basic and comprehensive metabolic panels, troponin I, CBC count, and urinalysis. Outliers were defined as more than 30 minutes for a CBC count, more than 40 minutes for chemistry mea-surements, more than 60 minutes for troponin I measurement, and more than 30 minutes for a urinalysis. We also measured the ED patient lengths of stay in these hospitals. All 11 hospitals used the same chemistry analyzer (Dade Dimension RxL, Dade, Deerfield, IL) for chemistry and cardiac testing; in hematology, different instruments were used (Abbott Cell-DYN, Abbott, Abbott Park, IL; Coulter, Beckman Coulter, Brea, CA); and for urinalysis, the Roche Criterion (Roche, Indianapolis, IN) strip reader was used.
Results
The hospitals included in this study ranged in size from 90 to 380 beds with annual ED volumes of 23,000 to 45,000 patients and 35,000 to 74,000 annual ED laboratory test orders
CBC count - TAT were: best :6 min; average::10 min; worst:12 min
Cardiac panel - TAT were: best:28 min;average:37 min; worst: 41 min
After improvement
CBC count - TAT were: best :0.9 min; average::2.5 min; worst:4.8 min
Cardiac panel - TAT were: best:1.8 min;average:5 min; worst: 8.1min
Changes in the emergency department (ED) length of stay (LOS) in relation to the percentage of laboratory turnaround time (TAT) outliers (July /05) were to 4Hs10 min to 3Hs 02 min
Discussion
For years, clinical laboratories have judged overall quality of services using mean TATs measured in minutes. However, TAT means vary greatly based on individual hospitals and the type of test under consideration. At the same time, the TAT OP varied even more between hospitals . To complicate matters further, shows that TAT means are not related consistently to the TAT OP among the 11 hospitals studied. For example, hospitals 6 through 9 show comparable TAT means but vary markedly in terms of the TAT OP.
We observed a significant relationship between the TAT OP and ED LOS ( Table 1 ). The regression equation suggests that for each 1-point increase in the TAT OP, the additional patient wait time in the ED is approximately 7 minutes. Extrapolation revealed that as the TAT OP approaches zero, the ED LOS should approximate 160 minutes. These assumptions will hold true only when the laboratory is the rate-limiting factor in the ED LOS. Although this typically is the case, in certain situations, the laboratory test TAT conceivably would not be a bottleneck for ED throughput.
Adding further strength to observed correlation between the ED LOS and TAT OP is the dynamic relationship , workflow improvements in 1 community hospital improved the TAT OP with concomitant decreases in the ED LOS. The ED LOS was reduced from 4.1 to 3.2 hours as the laboratory TAT OP decreased from 14.4% to 4.9%. By using the preceding regression formula, the projected decrease in the ED LOS for this amount of improvement in the TAT OP is 67 minutes, which compares favorably with the observed decrease of 55 minutes.
Conclusions
The TAT OP has a direct and significant relationship with patient wait times in the ED. Moreover, our findings indicate that improvement in core laboratory TAT OP will reduce ED patient LOS substantially. In addition, we found that the older methods for monitoring laboratory performance using test TAT means are not particularly useful in assessing the laboratory\'s impact on patient care. We conclude that the laboratory has a clear and significant role in the effective practice of real-time, evidence-based medicine in the critical care setting.
Am J Clin Pathol. 2005;125(5):672-674
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