Greater health awareness, and the growing prevalence of lifestyle illnesses, are driving new interest in point-of-care testing (POCT) and diagnosis. Many POCT services are already available, and the development of a broad range of increasingly compact, increasingly high-performance POCT devices is advancing rapidly. In this article, we offer an overview of the current status and future prospects of POCT.
What is Point-of-Care Testing?
POCT refers to medical testing and diagnosis carried out at, or close to, the site of patient care. For inpatients, POCT would be carried out at the patient's bedside or in a regular exam room. For outpatients, POCT can be carried out at the patient's home, at a local pharmacy, or at local clinic's examination room. (See Figure 1.)
POCT enables testing and diagnosis to be carried out rapidly and easily—so doctors and other healthcare professionals can respond more quickly, while patients benefit from the extra convenience and reduced stress. POCT also enables patients with chronic illnesses to monitor their status continuously in their everyday environment. Because POCT offers these significant benefits to both practitioners and patients, the market for these devices is growing and broadening.
In order to replace conventional devices with POCT, it will be necessary to design and build a broad range of small, portable POCT devices that can be easily transported and set up anywhere. It will also be necessary to build in higher-level functioning that reduces test times, and to create designs that cause relatively little discomfort so that patients can use these devices continuously.
Below we look at POCT devices that are already available, and at new ones currently under development, as we consider the outlook for POCT deployment over a broad range of applications.
Currently Available POCT Devices Diagnosing Diabetes and Influenza
POCT is now widely used throughout the world to help control diabetes. Diabetics must continuously monitor and control their blood sugar, and POCT devices enable them to do this on their own. Because POCT devices provide rapid results, they also help reduce the risk of developing the visual and neurological disorders that may be associated with this disease.
POCT is also currently used in diagnosing influenza. Conventional diagnostic agents do not work until the viral load has become significantly elevated—typically a half-day or longer after fever and other symptoms arise. POCT, in contrast, delivers rapid on-the-spot diagnosis.
From Sample Testing to Body Testing Emerging POCT Applications
Diabetes and flu tests require taking of blood and urine samples, which are then tested (typically in a laboratory) for cell counts and various constituents. While some POCT devices implement this sort of testing, other POCT devices do direct body testing, such as ultrasound tests and EKGs.
POCT ultrasound testing, in particular, has scored significant successes, and has worked its way into the mainstream of diagnostic techniques. POCT ultrasound delivers real-time imaging without need for large apparatus, enabling rapid diagnosis. Manufacturers are working actively to build additional functions and capabilities into these devices, to further extend their range.
One well-received POCT ultrasound device used both at homes and in clinics, is the pocket-sized Vscan from GE Healthcare Japan. The Vscan 1.2, launched two years after the original, is ideal for healthcare professionals working outside of hospital environments: it operates on low power, and can test for up to 90 minutes (up from 60 minutes with the original model) on a single charge. It is small and light: just 135 mm (5.3 in) long × 73 mm (2.9 in) wide × 20 mm (0.8 in) thick, with a weight of 390 grams (under 14 ounces).
The newest model, the Vscan Dual Probe, launched in 2014, is somewhat more advanced. With two transducers housed in its single probe, it is capable of both deep and shallow imaging. With a weight of just 440 grams (1 lb), it is finding growing use in the market. (See Photo 1.)
Photo1. Vscan Dual Probe
Photo2. Acuson Freestyle
The ACUSON Freestyle Ultrasound System, from Siemens Japan, is the world's first POCT imager with wireless ultrasonic probes. The probes can operate at distances of up to 3 meters (9.8 ft) from the main unit. The unit delivers general-purpose ultrasound imaging while eliminating the need to bring the patient to a dedicated room or to roll large equipment toward the patient's vicinity. Each probe includes a transmitter that sends data to the main unit for processing. (See Photo 2.)
The growing range of POCT devices offers improved testing efficiency in many areas. One example: the WatchPAT portable sleep evaluator, from Philips Respironics, offers at-home monitoring of individuals suffering from sleep apnea syndrome (SAS), a fairly common condition afflicting about 3 million people in Japan. The unit tracks finger arterial pressure and oxygenation, snoring, and posture. With conventional treatment, SAS is diagnosed through hospitalized testing. With the WatchPAT, testing can be carried out at home: the data from the sensors is stored into memory, and the accompanying software analyzes it and generates a report providing all the information typically required for a diagnosis, such as missed breath count, shallow breath count, sleep states, and more. (See Photo 3.)
Photo 3. WatchPAT
Going Forward: Rapid Development into New Areas
With awareness of POCT growing, many companies are actively developing next-generation products. For example, the Shiga Prefecture Industrial Support Center is working together with various companies and universities in a joint effort to develop a POCT system capable of delivering sophisticated diagnoses from a single drop of blood. The system opens the possibility for on-the-spot blood testing and diagnosis, something not available with conventional approaches, where larger quantities of blood and considerable wait time for lab results are required.
Another joint project—involving Immuno Probe, Fukaekasei, Kyushu University, Tokyo Dental College, Panasonic Healthcare, and others—is engaged in developing an intraoral bacteriological device suitable for diagnosing periodontal disease. This condition afflicts an estimated 6 million sufferers in Japan alone, and is thought to be linked to serious systemic illnesses such as diabetes, angina, and heart attacks. At present there are still no devices offering easy testing of oral bacterial counts; the development goal is to deliver a POCT device that uses electrical measurements to rapidly assess pathogen levels. Dentists can use the device for diagnosis during regular dental visits, while dental hygienists, nurses, and other professionals can use it to assess periodontal disease risks on the spot.
New Treatment Modalities
Photo 4. LifeVest
While "test, then diagnose, then treat" is the conventional approach to health issues, today there is also new emphasis on rapid detection and on prevention. Moving forward, we can expect to see more and more testing and diagnosis carried out at mid-size and small clinics, at pharmacies, and in the home. POCT devices will play a crucial role in supporting this trend.
We can also expect to see the three essential steps—testing, diagnosis, and treatment—moving closer together, with rapid diagnosis and treatment made possible through real-time data provided by emerging POCT devices. As POCT applications advance, they will cover the full spectrum from prevention to treatment, opening up new modalities for health interventions.
The LifeVest wearable defibrillator, for example, is an example of a POCT device that carries out all three steps. This wearable unit—developed by ZOLL Medical, part of the Asahi Kasei Group—continuously monitors the heartrate, and both detects and corrects any dangerous arrhythmias. The unit is equipped with electrodes for both ECG measurements and the administration of defibrillation pulses.
As POCT devices become easier to use, they are likely to find broad applications in rural areas with relatively few healthcare providers. By enabling effective responses at the local and household levels, they will help people in these areas receive effective treatment without having to travel to large medical centers. And their speed in delivering test results will allow treatment to start more quickly, when it is likely to be most effective. And because POCT devices can include communication functions, they can also reach out to major medical centers in those cases where this becomes necessary. For example, they can instantly transmit the data they collect to the patient's electronic medical record, which in turn can be instantly accessed and responded to by professionals at any major center.
As POST devices improve, therefore, we can expect to see them play a growing role in bringing patients and health facilities closer together, to the benefit of both.