By Deborah Borfitz
September 16, 2020 | Diagnostic stewardship was a trending topic at the recent Next Generation Dx Summit, and the highlights included presentations by Christopher Doern, director of clinical microbiology at Virginia Commonwealth University (VCU) Health System and the Medical College of Virginia, and Matt Binnicker, director of clinical virology and vice chair of practice in the department of laboratory medicine and pathology at the Mayo Clinic. Both offered practical advice and tips for improving patient care under real-world budget and workforce constraints.
Antimicrobial stewardship programs provide a good model for optimizing the use of lab testing, according to Doern. The focus needs to be holistic, including ordering the right test and ensuring results are seen and understood. And efforts can be coordinated within the confines of the lab. Medical technologist are a great starting point, he adds, because “they know what’s going on and when things don’t make sense.”
Many diagnostic tests get unnecessarily repeated, Doern notes. It is often unknown how long nucleic acid hangs around in the body, but a 2016 study found that 60% of flu patients continued to test positive long after clinical symptoms of the virus had resolved.
Repeating a test following a negative result can also be problematic, continues Doern, particularly if the goal is to “rule something out.” After determining that conversion of a negative to a positive result from nasopharyngeal swabs took an average of just under six days, a seven-day restriction was placed on repeating such tests in his lab.
Duplicate ordering of microbiology tests within 24 hours could also be reduced to a very small list, Doern says. “It’s the lowest of the hanging fruit.”
The Fungitell assay, one of the lab’s highest volume and most costly tests, has been repeated over 1,600 times on 464 patients since 2011, says Doern. The retesting often happened within three days, before results on the initial test are back. As a counter-measure, VCU Health System started reporting out previous results to ordering physicians when they went to order the same test a second time. But a blanket policy prohibiting retesting within four days—the average effective turnaround time—might also make sense, he adds.
Efforts to optimize the use of lab testing at VCU Health System began with high-burden activities, notably urine cultures, Doern says. Urine reflex testing has been successfully used as a preliminary screening test to lower the number of cultures performed on negative specimens.
Control of reference lab testing has involved consolidating on a single Lyme disease serology test, doing more tests in-house and simply putting a dollar sign next to high-volume testosterone tests so ordering doctors are aware of the exorbitant cost and preferred alternatives, he says.
It is up to labs to ensure diagnostic test results are understood, Doern says, noting findings of a 2013 study showing widespread physician discomfort with antimicrobial susceptibility testing. Physicians are so overwhelmed by the volume of results labs are producing that many of them never get reviewed at all.
Calling doctors with test results is the best way to get them to act on results, but microbiologists find this overly burdensome because “providers refuse to take their call, they have trouble finding patients in the outpatient setting and they don’t have the time and manpower,” says Doern. Practicality requires that the practice be reserved for critical findings with a significant impact on patient care. Patients of the VCU Health System also share in the responsibility via a portal that provides links to additional care.
“[Diagnostic stewardship] is a big problem but a big opportunity as well,” Doern concludes. “We own most of the data—start there.”
Team-Based Approach
As defined by Binnicker, diagnostic stewardship means reducing the use of overutilized tests and increasing the use of underutilized tests. The primary goal is to reduce the overall cost of healthcare while also improving the quality of healthcare delivery.
U.S. healthcare spending grew 4.6% in 2018 to over $3.5 trillion, or roughly $11,000 per person, Binnicker says. That represents 18% of the gross domestic product—more than any other developed country. Lab tests account for 2%-3% of total healthcare costs ($83 billion in 2017).
In the past, labs were “practicing to volume,” per the prevailing financial incentives, says Binnicker. “But now and moving forward, more labs will be incentivized to perform the right tests.”
The lab can’t solve the problem on its own, says Binnicker. He advocates for a multifaceted program with a multidisciplinary team and diagnostic stewardship committee, all centered on collaboration with an evidence-based algorithm as a key component. Feedback and auditing are also important, he adds, so physicians know how they’re performing relative to their peers.
As deployed at the Mayo Clinic, goals include “right test, right patient, right time”, enhancing the clinical utility (i.e., impact on patient management) of test results, and consideration of the financial impact to the lab, patient, and healthcare institution when a test gets ordered. “Quality and clinical value are paramount,” Binnicker says.
One cited example was increasingly costly respiratory pathogen testing, especially multiplex respiratory panels, which in some scenarios also has “interpretation challenges,” he continues. Among the stewardship measures implemented:
- Review of orders. Providers are contacted when orders originate in primary care or the emergency department. Administrative changes were also made to the electronic ordering system and care process models (i.e., ordering algorithms) were developed.
- Order entry guidance. If physicians input “cough,” for instance, the recommended test gets listed first. The verbiage accompanying the entry for multiplex panels makes note of the high cost, prolonged viral shedding by immunocompromised individuals and not to repeat testing within seven days.
- AskMayoExpert. The online compendium of Mayo Clinic-vetted medical knowledge is designed for use at the point-of-care by providers seeking answers to questions outside of their areas of expertise and is driven by a search engine. Physicians can get information on clinical diagnosis of the flu and if testing needs to be performed. When a flu is widespread, testing can be limited to hospitalized patients, Binnicker says. A link is provided to the preferred test in the ordering environment.
A second example shared by Binnicker was a Mayo analysis of serology testing for herpes simplex virus (HSV), which gets performed about 50,000 times annually despite “known limitations.” Patients don’t become seropositive for seven to 10 days and can remain that way for months, he notes.
The additive clinical utility of HSV serology testing when ordered with polymerase chain reaction (PCR) testing was found to be limited, prompting Mayo to “discontinued [serology] testing altogether,” Binnicker says. Results of that study, which were subsequently published in the Journal of Applied Laboratory Medicine (DOI: 10.1373/jalm.2019.030890), found that serology testing by itself had only a 2.3% positivity rate and among patients who had both tests, 50% of them were identified as positive (based on PCR) and negative (serology results).
The financial impact of the move was significant, he adds, including $130,000 per year in savings for the lab, $50 per test for patients, and $2.5 million annually in overall healthcare spending.