The use of data linkage as a tool to evaluate laboratory work processes and patient care performance indicators

Introduction
This study describes a large data linkage exercise and quality performance assessment of test utilisation volumes and turnaround times (TAT) in a pathology service.

Methods
Pathology test data for six NSW hospitals, supported by a single pathology service, were extracted from the laboratory information system (LIS) for the August-September period of 2008–2011. Datasets containing admission/discharge, patient demographic, Diagnosis-related Group (DRG), triage category, and mode of separation data, were extracted from each PAS and EDIS. Unique patient identifiers were used to link individual test order records with either the PAS or EDIS datasets, or both. The final dataset was established after validity and integrity testing of source data.

Results
Data linkage occurred for approximately 2.8 million pathology tests (from the LIS), 147,280 inpatient admissions (from the PAS), and 176,015 emergency department (ED) presentations (from the EDIS). This resulted in approximately 1.3 million records linked to an inpatient admission only, 158,957 linked to an ED presentation only, and 385,817 test records linked to both an inpatient admission and ED presentation; a success rate of 66%.

Conclusion
The linked dataset facilitated analysis of test order volumes for matched patient conditions (DRGs). It also permitted the generation of statistical regression models to assess the impact of laboratory performance indicators (e.g. TAT) on indicators of patient care (e.g. length of stay).