Background: Automated platforms are available for the detection of sexually transmitted infections using molecular assays. The choice of a suitable system for diagnostic laboratories depends on a number of factors. Comparative workflow studies of automated instruments provide quantifiable and objective metrics for hands-on time during specimen handling and processing, reagent preparation, return visits, maintenance, allowing calculation of test turnaround time and throughput.
Methods: Using objective time study techniques, we measured workflow and maintenance characteristics of four automated batching instruments, TIGRIS (Hologic/Gen-Probe), m2000 RealTime (Abbott), cobas 4800 (Roche) and Viper XTR (Becton Dickinson), and the PANTHER instrument (Hologic/Gen-Probe), which is a continuous random access system. Comparisons were made for 96 and 192 tests using respective second generation Chlamydia trachomatis molecular assays on first catch urine and self-collected vaginal swabs.
Results: PANTHER showed the least overall hands-on time and Viper XTR the most for testing and maintenance. Both PANTHER and TIGRIS showed greater efficiency than the rest when processing 192 tests. Viper XTR and PANTHER had the shortest times to results and m2000 RealTime the longest. Cobas 4800 had the longest sample preparation and loading time. Mandatory return visits were required only for m2000 RealTime and cobas 4800 when processing 96 tests. All instruments required return visits when processing 192 tests, with both m2000 RealTime and cobas 4800 requiring more return visits and substantially more hands-on time than the rest.
Conclusions: There were substantial differences in the amount of labor required to operate and maintain automated diagnostic laboratory instruments which are influenced by batching versus continuous random accessing and the number of specimens that can be batched. In addition to assay performance and testing capacity, laboratories should also consider workflow and maintenance characteristics of automated systems.