Point-of-Care Testing Continues Growth

Greater speed and accuracy mark POC trends

By Gary Tufel

Sometimes referred to under the heading of “near-patient” or “bedside” testing, point-of-care (POC) diagnostics encompass a variety of test platforms that sometimes appear to have very little in common with one another. What they do have in common is their focused ability to provide simple, rapid testing, often of blood or urine samples, and to be administered physically close to the location of the test subject. Some are administered in medical settings, and some at home; some are simple kits meant for use in settings where electricity and other resources might not be readily available, and some are sophisticated instruments with broad information technology capabilities.

Margery Rothenberg, Chembio.

Based on the philosophy “the sooner the better,” the need for POC tests in all medical areas is growing in importance, according to Margery Rothenberg, senior director of global marketing at Chembio Diagnostic Systems Inc, Medford, NY. “The sooner we can diagnose a problem with accuracy, the sooner we can treat it,” Rothenberg says.

Currently marketed POC tests include a wide range of small, lightweight, uninstrumented kits that can provide rapid results for many diseases and conditions, including blood glucose, drugs of abuse, infectious diseases, and pregnancy. The POC market also encompasses a growing number of more complex and sophisticated countertop instruments, each capable of performing tests for a defined menu of diseases and conditions in many near-patient settings. The menus of both uninstrumented and instrumented POC devices are continuing to evolve and expand and, in some cases, the formats may even be converging. (For more information, see the companion article, “Reimagining the Immunoassay Method, at the Point of Care.”)

THE IMPORTANCE OF POC

Thomas I. Koshy, PhD, senior director for scientific affairs at Alere Inc, Waltham, Mass, says that point-of-care testing is most important when it can fulfill one of three needs:

• Providing clinical information in acute care settings faster than it could be delivered by a conventional laboratory. Common examples include emergency department troponin tests, or blood gas measurements in a critical care unit.

• Providing clinical information that enables the healthcare provider to take advantage of a teachable moment. In a doctor’s office, for example, a flu or Strep test can help patients understand when they do (and don’t) need a prescription for an antiviral or antibiotic. An HIV test given to a high-risk individual who is unaware of their infection, can lead to rapid counseling and initiation of therapy.

• Providing clinical information in settings where conventional laboratory equipment and facilities are unavailable or impractical. Examples include remote locations; mobile healthcare setups; and temporary emergency medical environments, such as those following natural disasters.

Thomas I. Koshy, PhD, Alere Inc.

“It is becoming technically feasible to put the laboratory on a chip at the patient bedside, but operational, analytical, and economic factors do not yet make this a practical option,” says Koshy. “In the past 10 to 12 years, large laboratory analyzers have become exceedingly efficient and cost-effective. As POC technologies evolve to satisfy needs in the areas where they are most important, POC devices will naturally become easier to use, more analytically accurate, and more cost-effective. Then, they can be a viable routine alternative to laboratory testing.

“There will certainly come a time when small, portable, battery-operated devices will compete with the performance, speed, and cost of conventional laboratory equipment for all conventional laboratory testing,” he adds, “but that date is probably far off.”

But in the meantime, will the two types of POC test formats ever evolve to where there’s no distinction between uninstrumented and instrumented POC tests? Or will there always be a need for both formats to meet the needs of specific kinds of testing?

Doug Simpson, Corgenix Medical Corp, and Tulane University School of Medicine.

Douglass T. Simpson, senior advisor to the Viral Hemorrhagic Fever Consortium at Tulane University School of Medicine, and infectious diseases consultant to Corgenix Medical Corp, Broomfield, Colo, expects that there will always be specific needs for both instrumented and uninstrumented tests. “In Western medicine settings the push may be greater toward instrumentation,” he says, “whereas in more resource limited areas such as Africa, that creates additional barriers.”

“I believe there will always be a need for specific instrumented and uninstrumented kinds of tests,” agrees Rick Betts, acting vice president of medical division sales and marketing at Abaxis Global Diagnostics, Union City, Calif. “But general POC chemistry testing has already evolved into a panel-based system for routine tests, such as the basic and comprehensive metabolic panels, lipid panels, and so on.

“Beyond that, POC technology will continue to evolve with technologies that make testing easier and more capable,” says Betts. “Automation of hematology, immunoassay, and chemistry combined are what the market needs to deliver a truly robust POC solution for primary care. This is where the market of ‘instrumented’ tests is heading: one device that can do it all.”

DIFFERENT SITUATIONS, DIFFERENT FORMATS

Filling a test cartridge for the Piccolo Xpress POC clinical chemistry analyzer by Abaxis Global Diagnostics.

The different formats do have specific advantages in certain situations. For Simpson, uninstrumented tests are best for remote testing, testing by lower-level trained individuals, and testing in resource-limited environments. Instrumented tests, on the other hand, are tailored to hospitals and other centralized testing sites.

“Uninstrumented tests tend to be qualitative (eg, pregnancy and flu tests) or semiquantitative (pH strips), and are best when a yes/no or ballpark answer is sufficient,” says Koshy. “Instrumentation became necessary when quantitative results became a need, such as for measuring the brain natriuretic peptide levels of a patient with suspected heart failure, or the coagulation status of a patient on an oral anticoagulant.

“There will always be a market for uninstrumented rapid tests, but improvements are in the works,” says Koshy. “A number of companies, Alere included, have developed or are developing ‘readers’ for lateral-flow tests that will reduce human error and subjectivity in the interpretation of the test results. In addition, the readers will provide a mechanism by which the uninstrumented test result can be electronically captured into the medical record.”

Quantitation of traditionally qualitative results has always been preferred, but has often not been technically practical. But now, says Koshy, POC technology is rapidly developing to the point where quantitation of previously qualitative tests is practical. “Already, there is a quantitative whole-blood human chorionic gonadotropin (hCG) test for pregnancy on the market,” he notes. “In addition, nucleic acid amplification is rapidly becoming the state of the art for infectious disease tests, and reading the results of such testing requires the use of a small meter.”

In some settings, having no required instrumentation can advantageously streamline the point-of-care testing process. In others, readers can minimize operator error and link results to a patient’s electronic health record, which can facilitate continuity of care. “The advantages and disadvantages depend on the venue and how one specifically defines ‘point of care,’” says Chembio’s Rothenberg. “How accessible does the test need to be? Is electricity readily available? Can the instruments be operated with batteries?” she asks “Additionally, ever-evolving technology will present us with new POC tests—with and without instrumentation.”

CONVERGENCE FAVORS POC INSTRUMENTS

Whether manufacturers can expand the menus of such devices depends on the platform. “In general, companies attempt to build in expansion capability so that the menu can be enlarged—typically a necessity to make the products economically feasible,” says Corgenix’s Simpson. “With instrumentation, there will always be a push for menu expansion.”

Inserting a test cartridge into the Piccolo Xpress POC clinical chemistry analyzer by Abaxis Global Diagnostics.

Specific tests may require different types of testing platforms, but a convergence between test kits and larger POC devices looks likely. Moreover, even laboratory benchtop devices may eventually be consumed by POC devices as they become more capable.

“Benchtop usually means batching of samples, which is more efficient for sample processing, but less efficient for delivery of care,” says Betts. “The whole idea is to do more with the patient during the first encounter. Follow-up visits for services that can be performed at the initial point of care are unnecessary and are what clogs the system. So, the ultimate model is pointing to anything and everything that is possible to be done POC, will be done POC.

“This includes genomics. Labs will centralize further and will be utilized for batching when that makes sense, and will be used for highly specific testing that requires the expertise of laboratorians,” says Betts. “General screening and diagnosis will be done at the point-of-care, and more specific testing at the lab.”

Implementing such convergence will require most POC locations to develop standard protocols for types of patient presentations that require general labs. They will also need to undertake patient flow management, so that bottlenecks are not created and rooms are not occupied any longer than they have to be. Additionally, says Betts, employers will be playing greater roles in the care of their employees. “Incentives by insurers to conduct employee check-ups and identify conditions earlier are currently taking shape across the country,” he says.

SOME CURRENT POC PRODUCTS

Instruction card for the ReEbov rapid diagnostic test for ebola from Corgenix Medical Corp.

To assist doctors in diagnosing ebola virus disease quickly, the US Department of Health and Human Services recently announced that it will pursue development of an ebola virus diagnostic test for use in a doctor’s office, hospital, clinic, or field setting that will provide results within 20 minutes.¹

“Fast and inexpensive POC diagnostics will improve our ability to control ebola virus disease outbreaks,” said Robin Robinson, PhD, director of the HHS Biomedical Advanced Research and Development Authority that will oversee this development program. “Faster diagnosis of ebola virus infections allows for more immediate treatment and an earlier response to protect public health worldwide.”

Development of the ebola test will take place under a $1.8 million contract with OraSure Technologies Inc, Bethlehem, Pa. The company’s lateral-flow tests detect the presence of a virus with a drop of the patient’s blood or saliva on a test strip, similar to the tests used in doctors’ offices to diagnose strep throat.

Diagnosing ebola virus infections quickly in resource-poor areas would enable healthcare providers to isolate and provide necessary treatment and supportive care to patients suffering from ebola. Quickly isolating patients helps limit the spread of the disease. Emerging evidence has shown that early initiation of supportive care improves outcomes for patients suffering from ebola virus disease, said the HHS announcement.

The ReEbov ebola test kit from Corgenix Medical Corp.

Corgenix is also developing a test for ebola, but the company’s efforts have not stopped there. “In addition to Corgenix’s ebola virus POC test, the company also has a similar rapid POC test for Lassa virus, another hemorrhagic fever virus endemic in West Africa,” notes Simpson. “The Corgenix collaboration with Tulane University and other members of the Viral Hemorrhagic Fever Consortium continues to result in advances in diagnostics in this area. These products are positioned for rapid field use to quickly diagnose and institute medical countermeasures rather than wait for sample transport or patient transport to complete the diagnosis.”

And in addition to infectious diseases, Chembio is currently working on POC tests for cancer and traumatic brain injury, including sports-related concussion, Rothenberg says.

The Piccolo Xpress POC clinical chemistry analyzer by Abaxis Global Diagnostics.

The Abaxis Piccolo Xpress occupies a unique niche as the only POC device able to perform comprehensive chemistry under a CLIA waiver, notes Betts. “We are the only ones to provide liver function testing and a complete ‘statin’ panel for hyperlipidemia management. There are currently 31 tests on the Piccolo Xpress menu, and 26 of them are CLIA waived. This is by far the most.

“The instrument’s menu continues to expand, and we are continuing to look for ways to become that ‘Nirvana’ instrument that everyone is looking for. We’re also looking for ways to continue reducing the cost of our technology so that it can be implemented in a wider variety of healthcare settings,” says Betts. “And we look forward to a day when the government and insurers in the United States can agree that POC testing is good and that, despite its increased costs versus the lab, it reduces the overall cost of care while improving wellness.”

THE FUTURE

For the future of POC testing, Chembio’s Rothenberg foresees tests that offer faster turnaround, easier performance (fewer steps and minimal training), and smaller specimen requirements—and maybe even specimens obtained noninvasively. Such accurate POC tests across a broad range of analytes will be accessible to physicians and other healthcare professionals, public health specialists, pharmacies, and patients.

While POC tests may continue to be compared to their laboratory counterparts with regard to analytical performance, accuracy, sensitivity, reproducibility, cost, and other factors, such comparisons are not always appropriate. “It is extremely important to consider the POC test in light of the clinical application and setting where it is to be deployed,” says Koshy. “POC glucose meters are not analytically equal to laboratory glucose tests, but they are perfectly suitable for the home management of stable diabetic patients. In other words, they are accurate enough for that application.

“The next-generation POC troponin tests may be less analytically sensitive than their next-generation laboratory counterparts,” says Koshy. “But they will still be more than sensitive enough for the detection of heart attacks in the emergency room.”

Gary Tufel is a contributing writer for CLP. For further information, contact CLP chief editor Steve Halasey via [email protected].

REFERENCE

1. HHS pursues fast, easy to detect Ebola virus infections [press release]. Washington, DC: US Department of Health and Human Services, 2015; available at www.hhs.gov/news/press/2015pres/06/20150612a.html. Accessed August 24, 2015.