Clinical Utility Importance and Application to Microbiological Tests

Aug. 6, 2019

Adding new tests in the clinical microbiology laboratory requires the input of many. Not only must the clinical microbiologists demonstrate validity of a new test, but also the administration must approve any cost incurred by running the tests. Communicating the benefits of a new test, or its clinical utility, can help all parties make a decision on how to implement new tests. This is especially important as new tests are developed using the latest technologies.

JCM Article: Clinical Utility of Advanced Microbiology Testing Tools

What are the hurdles for new test implementation, and how will defining a test’s clinical utility determine whether it is implemented? What is clinical utility, anyway? These questions are addressed in a new Journal of Clinical Microbiology article. We spoke with first author Dr. Melissa Miller to better understand the subject.

What Kinds of Tests Are 'Advanced Microbiology Testing Tools'?

Melissa-Miller-April-2017-small.jpgMiller: In the current environment, these are largely molecular-based tests. However, it could also be advanced technologies for rapid susceptibility testing or isolate identification.

Who Benefits from Applications of Advanced Microbiology Testing Tools?

Miller: Ideally, everyone – the diagnostic company, the laboratory/institution, and most importantly, the patient.

How Do These Tools Improve Diagnostics and Patient Outcome?

Miller: Most labs currently hypothesize or estimate the impact these technologies would have on the lab, such as improved laboratory workflow or throughput. In general, as technologies evolve, tests are more accurate. These data can be captured relatively easily.

What is not as easy is the impact on patient care and patient outcomes. For example, how does the test decrease unnecessary antibiotics, improve patient mortality or shorten hospital length of stay. These impacts are more difficult to measure, but are critical in determining the role of new, often more expensive, diagnostic tests.

Why Haven't All Healthcare Facilities Implemented Advanced Microbiology Testing Tools into Their Work Flow?

Miller: There are probably two main reasons: cost and expertise. Cost remains a hurdle for many laboratories, and this will become an even bigger factor as reimbursement rates decrease for laboratories. However, we are seeing a trend towards simplification of assays (i.e., moderate-complexity testing or CLIA-waived testing) that allows for advanced diagnostics such as multiplex PCR to be performed by less-experienced personnel.

What Does It Mean for a Diagnostic Test to Have Clinical Utility?

Miller: I can't really state it better than we did in our article, where we wrote: "Clinical utility of a test is related to the added value it has for patient management. A test has utility if its results (positive or negative) provide information that is of value to the patient and the provider in making decisions about effective clinical care. It can take the form of improved efficiency in clinical decision-making, streamlined clinical workflow, better patient outcomes, and/or cost offsets or avoidance."

How Are Patient Outcome, Clinical Workflow, and Costs Prioritized When Deciding if a Test has Clinical Utility?

Miller: In my opinion, improved patient outcomes always trump the other considerations (clinical workflow or costs). Often one can measure improvement in costs to care even though there may be an increase in cost to the laboratory. From a payer perspective, they are most interested in patient outcomes. For example, does the test directly impact the management of the patient. It is no longer sufficient to hypothesize the impact, we are being pressured by our institutions and payers to prove how laboratory tests are improving patient care.

How Is a Test Shown to Have Clinical Utility? Why Is It Important to Carefully Design Studies that Test Clinical Utility?

It is important that these studies are well designed, including appropriately powering the study, so that valid conclusions can be made.

Miller: Ideally, a study specific to the patient population of interest is conducted and real world clinical outcomes are measured. The clinical data are generally gathered through chart review. Many factors contribute to clinical outcomes, of which diagnostics can be one. Therefore, it is important that the study period with the new diagnostic device is compared to outcomes obtained without the diagnostic device. It is more convenient to do a pre- post-test implementation study, though a randomized controlled trial is more powerful.

It is important that these studies are well-designed, including appropriately powering the study, so that valid conclusions can be made.

When Do You Expect a Broader Community Appreciation of the Value of Advanced Microbiology Testing Tools?

Miller: There are more conversations now than ever before. The interaction between industry, microbiologists and payers is increasing. ASM has sponsored a number of events including the Corporate Council meetings, an ASM workshop at Microbe, and the Clin Micro Open that is fostering these relationships.

One of the priorities for the ASM Clinical and Public Health Microbiology Committee this year is to follow up on the JCM manuscript to develop tools for laboratorians and colleagues that will enable them design and effectively implement clinical utility studies aimed and determining how advanced microbiology tests can be best used to benefit the patient. Of course, these studies cost money, so partnering with industry and government sources for funding will be necessary. In my experience, many diagnostic companies also have significant expertise in designing and implementing outcome studies. Clinical laboratorians should draw upon the expertise that already exists.

Author: Julie Wolf, Ph.D.

Julie Wolf, Ph.D.
Dr. Julie Wolf is in science communications at Indie Bio, and is a former ASM employee.