CLN - Feature

What’s Next on the Point-of-Care Testing Menu?

From SARS-CoV-2 to cardiac biomarkers, a steady stream of IVD innovation shows no signs of letting up

Kimberly Scott

While point-of-care (POC) testing in recent years has drastically altered how patients are treated for conditions such as diabetes, HIV, and cardiovascular disease, new advancements on the horizon are expected to vastly improve near-patient treatment for strokes, infectious diseases, and cancer, according to experts.

In vitro diagnostics (IVD) companies are working to improve specificity and sensitivity of devices so that testing can be done on smaller specimen samples, said Nick Collier, PhD, chief technology officer for Sagentia Medical, a contract research organization based in the U.K. “There is a lot of interest in reducing sample size—using capillary blood samples to do testing, for example.”

At the same time, technology is getting smaller, cheaper, and more sophisticated. Lab-on-a-chip (LOC) devices, which require just a few drops of blood, already are in use and potentially could be more widely deployed, especially in areas with limited healthcare resources. In addition, diagnostics companies increasingly are combining different technologies into single platforms so users can perform multiple tests on one sample, Collier added.

Abbott’s i-STAT 1 POC blood analyzer, for example, can run multiple tests on one cartridge, including tests for cardiac markers, coagulation, blood gases, chemistries, electrolytes, and hematology. Roche Diagnostics’ cobas Liat PCR System also performs multiple tests, using polymerase chain reaction technology to test for influenza A/B, respiratory syncytial virus, and group A strep in about 20 minutes.

Roche is in the process of developing assays for other infectious diseases, said Corinne Fantz, PhD, director of Roche Scientific Affairs. “We have a goal to make molecular testing for sexually transmitted diseases [STDs] available at the point-of-care,” she explained. “Having the ability to test for STDs in a doctor’s office will have a big impact on treatment. The physician would be able to get the results before a patient leaves the office, which means they can have a discussion with the patient and decide on treatment.”

Also on the infectious diseases front, the COVID-19 pandemic has spurred development of POC tests for SARS-CoV-2, the virus that causes COVID-19. In the United States, Cepheid was first to market with a rapid, near-patient test that it says will give results in 45 minutes. The Food and Drug Administration (FDA) on March 21, 2020, issued an emergency use authorization (EUA) for Cepheid’s Xpert Xpress SARS-CoV-2 test for use in high- and moderate-complexity CLIA labs. Mesa Biotech (San Diego) received an EUA March 24 for a test that gives results in 30 minutes, and Abbott Labs received an EUA March 27 for a POC test that can deliver positive results in as little as five minutes. Other companies seeking FDA approval for POC COVID-19 tests include Becton Dickinson, bioMerieux, Integrated DNA Technologies, LabCorp and Quest Diagnostics. In addition to molecular tests that analyze the viral RNA in patient throat/nasal swabs, other POC testing methods that are pending approval use immunoassays to detect COVID-19 antibodies in blood or serum.

Other companies seeking FDA approval for POC SARS-CoV-2 tests include Becton Dickinson, Bio-Rad, bioMérieux, Integrated DNA Technologies, LabCorp, and Quest Diagnostics. In addition to molecular tests that analyze the viral RNA in patient throat/nasal swabs, other POC testing methods that are pending approval use immunoassays to detect SARS-CoV-2 antibodies in blood or serum.

While there are more than 100 POC tests available in the U.S., not all are widely implemented, such as tests for proteins in blood used for cancer diagnosis, noted Kathleen David, MT(ASCP), POC testing manager for TriCore Reference Laboratories in Albuquerque, New Mexico. “Availability is one thing. Then there’s acceptance and implementation,” she said. “Some of these we will see in cutting-edge places in the next couple of years, but it will be longer before it filters down to POC in smaller hospitals or other settings.”

What is on David’s POC testing wish list? “Procalcitonin for sepsis, which would be useful in terms of curbing antibiotic resistance,” she noted. “A fingerstick [complete blood count] test would also be wonderful. But one of the problems with POC testing is that if you want widespread adoption, you have to get a CLIA waiver. For doctors’ offices and clinics, getting a waiver is relatively doable, but getting a certificate of compliance has more requirements and isn’t always possible for most clinics.”

“There is a lot of interest around sepsis diagnosis and treatment,” agreed Collier, noting that only a few rapid tests for sepsis exist. An example is BioFire’s BCID Panel that tests for 24 gram-positive, gram-negative, and yeast pathogens, as well as three antibiotic resistance genes associated with bloodstream infections. Abbott offers POC lactate testing that can be performed at a patient’s bedside. While the BioFire test does speed up pathogen identification, it is not yet POC because it requires the blood to be cultured. Collier noted that there is significant interest in whether the blood culture step could be avoided, with molecular tests performed straight from blood to identify the pathogen and antimicrobial resistance genes.

Another likely trend in POC testing is use of high-sensitivity troponin I (hs-cTn) tests in emergency departments and urgent care centers to diagnose heart attacks more quickly, Collier predicted. These assays, which were first introduced in Europe in 2010, have only recently become available for clinical practice in the U.S. Hs-cTn T allows for detection of very low levels of troponin T, helping to diagnose heart attacks faster than testing sent to the central lab, which in turn speeds treatment and improves outcomes.

When Does It Make Sense to Offer POC?

Most physician office labs offer about five or six POC tests, often for pregnancy, strep, and diabetes (glucose and hemoglobin A1C), said TriCore’s David. Urgent care centers that do moderate-complexity testing typically offer additional testing, such as D-dimer tests, complete blood count, and flu testing. At hospitals, POC testing—from prothrombin time with international normalized ratio to blood gases—is performed in various units.

Before deciding whether to offer a POC test, a healthcare provider should consider several factors, experts say. First, how will the test benefit patient care? “If it means that treatment gets done faster or a patient gets a prescription right away, then that is a strong consideration for offering a test,” David said. Second, can the site accommodate changes to workflow by offering a test—for example, drawing blood or having patients get swabbed before they even see a physician? Third, volume: Does the site have enough cases to warrant offering a test in-house? Fourth, what is the cost/benefit return? “A lot of the time a central laboratory can do testing cheaper than POC, but if you can free up a procedure room 30 minutes faster and that saves $2,000, that’s a no-brainer,” David said.

Determining the value of a POC test is critical to making decisions about whether to bring it in-house, commented Roche’s Fantz. “A common test in the emergency department is POC creatinine to determine if patients have problems with their kidneys,” she said. “It may be more expensive than sending to a lab but the value is in treating a patient faster to improve the throughput in crowded places like the emergency department.”

Hospital department leaders should have a conversation with central laboratory leaders before deciding to offer POC tests, advised David, who said the laboratory might be able to improve workflow or communication to better suit the needs of staff. If the lab can’t accommodate the changes needed, she suggested consulting with the hospital’s POC manager or coordinator to determine which test would be appropriate for clinicians’ needs.

Payment for POC also needs to be considered, Fantz added. “Increasingly, payors are looking for evidence that a POC test brings value over tests performed in a central lab. Test manufacturers typically generate this evidence, but times are changing, and the bar is getting higher every year.”

POC testing will almost certainly increase in the coming months and years as technology continues to advance. As healthcare resources are stretched during the current global pandemic, near-patient testing will play an even greater role in helping patients get treatment quickly and efficiently.

Kimberly Scott is a freelance writer who lives in Lewes, Delaware. +Email: [email protected]