By Karen Appold
It is estimated that in today’s hospitals, as much as 30% of all clinical laboratory testing is now being performed at the point of care (POC).1 But according to experts, POC testing is far from reaching the top of its growth curve. In fact, the availability and use of POC testing is continuing to expand not only in hospitals, but in clinics, outpatient surgical centers, transport vehicles, health fairs, pharmacies, and the home. Expansion for use in disaster environments, Third World countries, and remote locations is also occurring.
When looking to purchase a POC test, laboratorians should consider a wide range of factors regarding a product’s attributes and capabilities. Many of these revolve around operator and data-management features.
“From an operational perspective, ease of use is one of the most important factors,” says James H. Nichols, PhD, professor of pathology, microbiology, and immunology, and medical director for clinical chemistry at the Vanderbilt University School of Medicine, in Nashville, Tenn. “Operator-induced errors can be a problem with some POC devices. A number may or may not be correct if too much blood was added, if a clot got in the sample, or if a bubble or something else occurred that caused an incorrect result,” he says.
Another attribute to look for is whether the device can be connected to a laboratory information system or a physician’s office computer system. After all, getting the test result into the patient’s chart in a timely manner is critical.
Safety checks are important as well. “There needs to be a means of tracking competency,” Nichols says. “A device should have lockout features, so that lab professionals who aren’t trained to operate it can’t use it.”
Along similar lines, it’s also important to prevent transmission of infectious diseases to both the patient and the caregiver performing the POC test. “When choosing a device, review how it can be disinfected between uses,” says Deborah A. Perry, MD, medical director for pathology at the Children’s Hospital and Medical Center, Omaha, Neb. “The manufacturer’s guidelines should provide this information, along with guidance outlining proper performance to decrease risk of infection.”
Quality control (QC) lockout features are yet another important component. “If QC isn’t performed on the device—or if QC is performed and the device doesn’t pass—the device should lock up and not permit testing,” Nichols says.
Turnaround time is another important factor to consider. “Today, most POC tests take less than 15 minutes,” Nichols says. “A few newer molecular tests may take an hour to generate results, but that is still much less time than waiting several days for the results of a culture test.”
Of course, cost needs to be considered as well. “You need to determine whether the price is reasonable and fits into your budget,” Nichols says.
GROWING AREAS
Developments in POC testing devices are occurring rapidly. According to Nichols, molecular POC testing is a growing area—particularly for infectious diseases. “We are seeing it expand for respiratory virus testing,” he says. “POC testing has now become commonplace to test patients for the flu or other viruses. Severe acute respiratory syndrome (SARS) continues to be a concern as well.”
POC tests based on nuclear magnetic resonance (NMR) are also under development. NMR testing devices use a magnet and tagged molecules to detect the presence of infectious diseases or antigens in blood. Such tests can also be used to detect pregnancy, to quantify blood glucose levels, or to measure basic metabolites. But NMR testing has even wider applications—the US government has used it to detect airborne agents, making the technology a useful tool in the realms of both infectious disease and bioterrorism prevention.
Nichols also expects advances in microfluidics. “Newer developments in engineering and manufacturing will allow for fabrication of smaller devices and test cartridges with added capabilities over the next several years,” he says.
According to Perry, other areas in which POC testing continues to expand include diabetes testing (glucose and HbA1c), renal testing (creatinine), coagulation testing (prothrombin time/international normalized ratio), and cardiac testing (eg, brain natriuretic peptide, troponin). “Genetic testing may someday be performed on a POC device,” she says. Theranos, a company based in Palo Alto, Calif, is among the leaders doing research in this area.
BENEFITS ABOUND
The advantages of POC tests also benefit patients. For instance, a POC test may make it possible for a patient to get blood drawn at a physician’s office and not have to make a separate trip to the lab.
“Then the patient can conveniently get counseled about their treatment and receive a prescription before even leaving their doctor’s office,” Nichols says. He notes that this is the premise that underlies the rapid growth of minute clinics located within neighborhood pharmacies. “In less than an hour, a patient can get diagnosed and get treatment. Now that’s one-stop shopping.”
Another benefit to patients is that, in some cases, POC tests require a smaller blood sample—or even no sample at all. According to Perry, an example of the latter type is the BiliChek noninvasive bilirubin assessment tool by Philips Respironics, Andover, Mass, which is a transcutaneous device that uses light instead of a needle to screen newborn infants for hyperbilirubinemia.
POC testing also enables the variety of offered tests to be expanded, especially in smaller hospitals or facilities, Perry adds. For example, a small hospital may not be able to afford a large chemistry analyzer to perform troponin testing to rule out a myocardial infarction. However, a POC device may be able to perform this test.
PRODUCTS AVAILABLE NOW
Today’s POC devices offer many features that benefit laboratories, providers, and patients. While some newer products embody capabilities that have never been seen before, some more established products are tried and true and, in some cases, offer unmatched attributes. Here are some of the offerings currently on the market.
Analyzers
The GEM Premier 4000 critical care analyzer, introduced in 2006, measures pH, blood gases, electrolytes, metabolites, total bilirubin, and integrated CO-oximetry. “It is a comprehensive, fully integrated and easy-to-use system, providing lab-quality results 24/7, regardless of location or the operator’s level of training,” says John J. Ancy, a senior clinical consultant at Instrumentation Laboratory, in Bedford, Mass. The GEM Premier 4000 offers the only single-component, multi-use, 30-day cartridge that includes all analytic components needed for a broad test menu. No refrigeration is required, and it’s maintenance free.
At the heart of all GEM Premier systems is Intelligent Quality Management (iQM), a patented quality assurance system. The iQM system automatically and continuously detects, corrects, and documents errors in real time to ensure quality results and regulatory compliance. “When coupled with GEMweb Plus Custom Connectivity, managers can oversee all analyzers in the network for complete control,” Ancy says. Users have remote access to and control over any networked GEM Premier 4000, from the analyzer itself or a personal computer, both in and out of the hospital. New features offer additional management tools, including automated operator certification, admission discharge transfer, and POC order creation—all in a uniform testing environment.
Delivering results in just 35 seconds, Radiometer’s ABL90 FLEX POC analyzer offers turnaround time unmatched by other blood gas analyzers on the market, says Alan Beder, senior product manager for Radiometer America Inc, in Westlake, Ohio. Combined with the analyzer’s labor-saving features, the ABL90 FLEX enables clinical caregivers to spend less time on testing and more on patient care. Designed specifically for POC testing, the ABL90 FLEX is a test-select analyzer that measures 16 parameters—including blood gases, electrolytes, metabolites, and CO-oximetry—from just 65 ?L of whole blood.
With a footprint about the size of a sheet of paper, the ABL90 FLEX fits easily within the confines of a hospital’s clinical POC testing areas. The ABL90 FLEX delivers up to 44 samples per hour, making it equally well suited to high-volume applications. “Automatic quality management and easy replacement of consumables eliminate maintenance,” Beder says. When used with Radiometer’s pre-bar coded safePICO ABG syringe or aspirator, the ABL90 FLEX automatically mixes and identifies the sample, reducing the possibility of preanalytical errors.
Available since 2011, the RAPIDPoint 500 blood gas system is a cartridge-based POC analyzer for critical care testing available from Tarrytown, NY-based Siemens Healthcare Diagnostics. Providing results in approximately 60 seconds, the RAPIDPoint 500 analyzer offers a comprehensive menu of critical care tests for pH and blood gases, electrolytes, glucose, pleural fluid and lactate, and full CO-oximetry, including neonatal total bilirubin and total hemoglobin, all from a single, whole-blood sample. Additionally, the measurement cartridges last up to 28 days and contain a full complement of tests, which reduces downtime.
Equipped with fully automated calibration and QC, the RAPIDPoint 500 system is designed to help POC professionals satisfy organizational and regulatory compliance requirements. Plus, “the self-contained automatic QC cartridge operates without manual intervention, helping reduce POC staff’s administrative tasks,” says Jennifer Stockman, associate director of marketing for Siemens Healthcare Diagnostics. “An integrated bar code reader—conveniently located on the front of the system—offers a wide scanning area to accommodate patient and operator identification to ensure overall data entry integrity.” The RAPIDPoint 500 analyzer can be integrated with the Siemens RAPIDComm data management sys- tem, which offers centralized management of multiple Siemens blood gas, urine chemistry, and HbA1c diabetes analyzers and operators.
Analyzer and Test
Available from Great Basin Corp since November 2012, the Portrait toxigenic Clostridium difficile (C. difficile) assay, performed on the company’s Portrait analyzer, is a qualitative in vitro diagnostic test to detect toxigenic C. difficile in patient stool samples. The test uses automated blocked primer enabled helicase-dependent amplification (bpHDA) coupled with chip-based detection to identify gene sequences associated with toxin-producing C. difficile, says Wes Lindsey, PhD, MBA, vice president for product development at Great Basin Corp, in Salt Lake City.
Traditionally, C. difficile diagnosis has been accomplished through labor-intensive culture procedures, followed by cell cytotoxicity testing of the isolates. Great Basin’s technology delivers a simplified workflow, including minimal pipetting steps, which greatly reduces the opportunity for sample contamination. The assay uses an integrated disposable cartridge containing all reagents, and a four-to-five-step sample processing procedure that delivers results in less than 90 minutes. Furthermore, the system processes samples on demand, delivering results to diagnosticians faster than systems that batch samples.
Controls
The Liquid Cardiac Control from Randox Quality Control is ideally suited for use in POC testing, says Steven Jordan, global QC manager for Randox Quality Control, in Crumlin, Northern Ireland. This liquid, ready-to-use control provides assayed, instrument-specific target values and ranges for nine analytes—including NT-proBNP and D-dimer with cutoff levels for troponin I and T provided in line with internationally recognized levels.
Among Liquid Cardiac Control’s benefits are: 100% human serum reduces analytical errors; liquid control minimizes the risk of human error; convenient 2ºC to 8ºC stability allows easy transportation and storage; a convenient and easy-to-use format enables non-laboratory personnel to use it; and user-friendly, color-coded caps allow different levels to be identified quickly and easily. In addition, there’s no need to thaw the control before use, freeing up precious staff time. Liquid Cardiac Control can be used in conjunction with the company’s new interlaboratory data management program Acusera 24.7 Live Online—which offers access to peer group data from more than 20,000 laboratory participants. As part of the Acusera range of true third-party controls, high quality, accuracy, and reliability is guaranteed.
Launched in May 2004, Streck’s A1c-Cellular is the first and only HbA1c control on the market that uses intact red blood cells. A1c-Cellular tests the entire HbA1c procedure, including the lysing of the red blood cell—a step omitted with other controls. “This important step ensures that the entire system is working properly and provides accurate patient results,” says Justyna Tesmer, product manager for Streck, in Omaha, Neb.
A1c-Cellular is convenient to use. It does not need to be reconstituted, which reduces the potential for human error. It is available in two clinically significant levels. The product is a ready-to-use liquid control appropriate for immunoassay and ionic exchange HPLC methodologies and assayed for a variety of testing systems. The plastic cap vials can be pierced and allow for autosampling for HbA1c analyzers with such capabilities. A1c-Cellular has 180-day closed-vial stability and 30-day open-vial stability.
CueSee BGEM LVM is designed to verify the reportable range of blood gases, electrolytes, and metabolites on any blood gas instrument. It includes five levels of an aqueous QC material, with all target levels spanning clinically significant ranges. Launched in late 2013, “CueSee BGEM LVM was created in response to both customer and instrument manufacturers’ requests to improve analytical measurement range verification for pH, pCO2, pO2, Na+, K+, Ca++, Cl–, Glu, Lac, urea, creatinine, and Mg++”, says Deb Capraro Phaup, vice president at Eurotrol, in Burlington, Mass.
“The pO2 and pCO2 ranges are further optimized to achieve higher levels than traditional blood gas controls. It is ideal for routine QC, linearity, and calibration verification, analytical measurement range verification, method validations, and method comparisons,” she says. As an added bonus for CueSee BGEM LVM customers, Eurotrol offers CueSee Online, a free online data submission program that provides statistical and graphical analysis along with peer review data.
Karen Appold is a contributing writer for CLP. For more information, contact CLP Chief Editor Steve Halasey via [email protected].
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Reference
1. Point of Care Testing Topic Center. College of American Pathologists. Available at: http://tinyurl.com/ p3qyf59. Accessed November 20, 2013.
