Clinicians discuss pros and cons of point-of-care testing devices

Physicians no longer have to wait hours to get laboratory results. The growing use of point-of-care-testing devices now makes it possible for doctors to see in near real time vital information about their patients. But some doctors who have adopted the technology say a number of drawbacks still exist with these devices, and the growing use of them raises questions about patient safety.

Judy Mangion, M.D., a cardiologist at Brigham and Women's Hospital in Boston, uses GE Healthcare's portable ultrasound system, Vscan. She said the device, about the size of a cell phone, has had an impact on the way she and her colleagues deliver care. The device makes it possible to get a glimpse of what is happening in a patient's cardiovascular system more quickly than traditional ultrasound machines, which are less portable.

"These devices do allow you to get ultrasound imaging to people and places that might not easily have access," Mangion said. "It does improve access substantially."

However, the device is not without its detractors. Battery life is limited, images generated from the Vscan device cannot be uploaded to the hospital's picture archiving and communication system, and images are less detailed than full echocardiograms, Mangion said. Additionally, there are no standards for appropriate use, which she worries could lead to unnecessary full echocardiograms.

"What this device potentially does is open a can of worms in that, because it's relatively inexpensive and so portable, [clinicians] can start to think about using this as a screening tool," Mangion said. "That may lead to more comprehensive [tests] being requested."

These kinds of concerns are common in other point-of-care testing devices. While new technologies offer physicians a way to quickly assess patients' condition, the fact that the tools were developed recently means there is little to no consensus on how to use them most effectively. Yet, even with drawbacks, doctors are still eager to make use of point-of-care testing devices.

Dov Frankel, M.D., assistant medical director of the emergency department at Sinai Hospital of Baltimore, said he petitioned his hospital's executives to purchase Abbott Laboratories' i-STAT point-of-care testing system because of the rapid blood test results it delivers.

He most frequently uses the device to perform Chem-8 panels, which measure patients' blood for sodium, potassium, chloride, bicarbonate, blood urea nitrogen, creatinine, glucose and calcium. The device gives Frankel access to measures of these compounds, which he said provide critical information about a patient's condition in less than two minutes. Before point-of-care testing was available, sending samples to the lab and waiting for results could take more than an hour, he said.

Speed is particularly important among stroke patient cases. Frankel said that doctors need to know a patient's prothrombin time, which is a value measuring blood coagulation, before administering medications to stroke victims.

Physicians need to know the strengths and weaknesses of point-of-care testing devices.

"Time is of the essence there, and you don't have an hour to wait for that value," Frankel said. "There's no way someone is going to push that medication if you don't have that value."

Still, he added that the point-of-care testing device is no replacement for laboratory testing because the range of values the device can test for is more limited than full lab workups. There is as tradeoff between speed and inclusiveness.

John Petersen, director of Victory Lakes Clinical Laboratories and point-of-care testing, associate director of clinical chemistry, and professor of pathology at the University of Texas Medical Branch, takes a similar view of point-of-care testing. While rapid results represent an advantage, devices do not always deliver the best quality results.

For example, he said that point-of-care glucose meters can be less accurate than full lab blood sugar tests. This can make a difference for diabetes patients who are on tight glucose control plans. Any variation in test results could throw off a patient's medication regimen.

"I don't think glucose meters are accurate enough to do [tight glucose control]," Petersen said. "They get you in the ballpark, but if you need a really precise number, at this point they can't do it."

Ultimately, Petersen said physicians need to know the strengths and weaknesses of point-of-care testing devices. Just because they do not offer the most accurate test results does not mean they shouldn't be used. The portability and rapid results they offer can help steer a physician in the right direction, giving them an idea of a patient's condition and allowing them to start the patient on a treatment plan. This can buy the doctor time until a more complete workup is completed.

Mangion agreed. She said that properly training users on all the functions of a point-of-care testing device is the key to making sure it is used correctly and delivers the greatest benefit possible. Without proper training, clinicians may expect more out of the device than it can effectively deliver.

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