Utilizing matrix-assisted laser desorption ionization–time of flight (MALDI-TOF) mass spectrometry (MS) can yield substantial cost savings for laboratories over traditional microbiology methods, according to a study presented at the American Society for Microbiology general meeting (Boston; May 17-20). Over a single year, the researchers say that MALDI-TOF saved the microbiology laboratory 92 percent in just reagent costs alone. Although the up-front instrumentation cost is high, the cost of identifying an isolate can be very low. University of North Carolina (UNC) Hospitals purchased the MALDI-TOF MS in 2012 for approximately $250,000. Although the laboratory tested both the Bruker and bioMérieux systems, they ultimately purchased the system from bioMérieux, which is headquartered 10 miles away. “We found the system really revolutionary, and that is not exaggerating,” Peter Gilligan, Ph.D., director of the clinical microbiology-immunology laboratories at UNC Hospitals, tells DTET
. “The biggest advantage is that it is fast and quite accurate for 95 percent of isolates. It takes minutes to make identifications that previously took days.” In the cost-effectiveness study, 21,930 isolates were directly compared on MALDI-TOF MS and conventional methodologies from April 1, 2013, to March 31, 2014. These specimens consisted of enteric pathogens, enterococci, gram-negative nonglucose fermenters, staphylococci, streptococci, and yeast. Costs for MALDI-TOF MS were calculated two different ways: perfect identification and a “real world” identification that allowed for repeat spotting. The researchers found that traditional identification of the nearly 22,000 isolates would have cost $84,491 in reagents alone, compared to $6,469 for MALDI-TOF MS, yielding a net savings of 92 percent in reagent costs in an ideal scenario where only one identification was required per isolate. When including the time spent by lab technologists, cost savings totaled $118,260 for one year, an 82 percent reduction. “The cost savings are very clear for the microbiology lab. It will take two to three years to pay for the equipment from the cost savings generated,” Gilligan says. “What we don’t know yet is if the institution is going to receive other downstream benefits. An outcomes study is underway to examine the benefit beyond the laboratory.” The study was part of a presentation to hospital administrators justifying the purchase. “This was the most expensive piece of equipment—by quite a bit—my laboratory ever bought. We have tremendous credibility with the hospital administration, so they believed us when we told them there would be cost savings,” says Gilligan. “We have an ever-increasing workload, and the hospital wasn’t going to give us more people, but it did buy us this equipment that allowed us to become more efficient.” Currently Gilligan says that his lab identifies between 80 and 100 isolates in an eight-hour shift, which can be “comfortably” increased to 350 isolates in eight hours “if workload demanded this.” As information technology improvements connect microbiology laboratories throughout the UNC system, Gilligan is confident the existing MALDI-TOF system in his laboratory can handle increased volumes resulting from testing sent in from satellite facilities. “We have a community-sized hospital 20 minutes away; would you put a mass spec system there? Absolutely not,” Gilligan explains, when asked about the volume necessary to justify the expense of a MALDI-TOF system. “During the time of the study, we were doing [almost] 22,000 identifications per year and we are an 850-bed hospital. If you had 50,000 [identifications] it would pay for itself faster. Would it make sense for a 100-bed hospital? I’m not sure.” A key to making the calculation, Gilligan says, is accounting for the time frame in which the technology will become obsolete. This technology window used to be much longer than it currently is. “With blood cultures we used the same techniques for 25 years. There were different platforms, but the same general approach. With HIV testing we are in the fourth generation in 30 years, so about a 7.5-year window. With molecular testing we are running in closer to three-year cycles,” Gilligan says. “As for MALDI-TOF, for now this is the best microbiology technology there is.” However, Gilligan would advise other laboratories considering making the switch to MALDI-TOF to evaluate the financials using a three- to five-year technology window. Takeaway: Aside from the potential clinical advantage of having a significantly shorter time to results of pathogen identification, evidence is emerging as to the substantial cost savings and efficiency gains that employment of MALDI-TOF technology can bring to microbiology laboratories. Side Box: A Public Health Lab’s Experience With MALDI-TOF
The New York State Department of Health (Albany) Wadsworth Center (WC) Bacteriology Reference Laboratory fully implemented MALDI-TOF into its workflow in 2013. The laboratory evaluated its experience during the first 11 months of MALDI-TOF. It found that:
- 1,700 clinical isolates (1,400 unique specimens) have been analyzed.
- 100 genera (more than 200 species) were identified.
- Using only direct smear analysis MALDI-TOF MS testing resulted in an acceptable bacterial identification for 76 percent of the specimens.
- An additional 15 percent of specimens required the formic acid-acetonitrile extraction, while 9 percent resulted in no reliable identification.
- Half of the final bacterial identification reports were based on MALDI-TOF MS alone, while 37 percent required additional biochemical analysis for species identification.
- Since MALDI-TOF implementation, there has been a 60 percent decrease in the number of real-time polymerase chain reaction tests and a 40 percent reduction in 16S rRNA gene sequence analysis.
- There has been a 45 percent reduction in the average turnaround time for final identification reports.
“This reduction in testing requirements has allowed the WC to better operate with a decreasing state budget, decreasing microbiology staff and has allowed more time to focus on other public health activities,” writes lead author Lisa Mingle, Ph.D., in an abstract also presented at the American Society for Microbiology general meeting (Boston; May 17-20).