In clinical diagnostics, the fastest-growing segment is point-of-care testing (POCT). POCT consists of medical diagnostic testing performed close to the patient, instead of a traditional centralized hospital lab or offsite laboratory. Driving this growth and market demand is the ability to bring convenient testing and almost immediate results to the physician and patient. The market is also very broad, as point-of-care tests can be developed for many clinical indications including infectious diseases, glucose, cholesterol, cancer (tumor marker testing), urinalysis, diabetes, cardiology and blood screening. The ability to quickly diagnose a wide variety of diseases closer to where patients are enables improved patient outcomes, increased patient access and lower total cost of care. This market shift is changing clinical diagnostics device manufacturers' needs and approaches to design. This blog investigates a common POCT technique and the innovative components being designed specifically for these devices.
Molecular diagnostics technique
Molecular diagnostics techniques have become a common enabling technology in the point of care market. In its most basic terms, molecular diagnostics typically involves matching the DNA found in a patient sample (the patients own DNA or DNA from organisms in the sample) to target disease in a DNA test cartridge. If no match is found in the test, the patient doesn't have the targeted virus, bacteria or cancer marker, but if a positive match is made the patient can be quickly treated for that illness. Molecular diagnostics enables smaller diagnostic devices because all of the chemistry can be completed in a small compact cartridge. It also provides the ability to detect multiple targets at one time with one sample, referred to as multiple testing. Below is a basic example of a multiplexed point of care instrument by using Molecular Diagnostics techniques, and the types of components that are often involved in this circuit.
In the above diagram, you see a simplified fluidic circuit where a multiplex test would be completed in a micro-fluidic cartridge. In this example system, fluids in the cartridge are piloted by air pressure supplied by an internal pump and controlled using various valves and pressure control methods. This circuit includes the Parker Helix pump (a miniature high-pressure pump) to supply the gas pressure to an accumulator volume to store compressed air. A Parker OEM-EP pressure controller or VSO LowPro proportional valve is then used to maintain steady pressure in the accumulator for precise control of the microfluidic circuit. Miniature solenoid valves such as the X-Valve, C7, Series MX, are used to dispense specific reagents and move the sample through the process. These fluidic components have a compact and efficient design which helps reduce instrument size and are offered with a variety of features to meet the needs of the application. Two specific parts of this fluidic system that will be examined in greater detail are the Helix Pump and the X-Valve.
The Helix Pump
The Helix pump is a compact, high-pressure pump that is designed to enable the smallest and fastest point of care instruments with a width of only 49 mm [1.9"] height of 84 mm [3.3"], and a length of 87 mm [3.5"]. The Helix pump delivers more than 5.5 LPM flow and pressures up to 100 PSI to pilot micro-fluidic cartridges with narrow passages. This compact pump was developed specifically for point of care test devices with limited available space and high-performance demands. The pump also includes an integrated Parker X-Valve to relieve pressure on the pump between cycles, this integration further reduces the footprint of the pneumatic system.
The increased performance of the Parker Helix pump also enables operation in challenging high-altitude environments with lower atmospheric pressure, allowing POCT systems to function in a broad geographical range, further increasing patient's access to life-saving diagnostic testing. The Parker Helix pump uses a controllable brushless DC motor designed to operate at a wide range of speeds to reduce noise in a system during times of lower demand. Additional accessories include a filter muffler, which provides further noise reduction and filters debris.
The X-Valve is described as a miniature valve but it is tiny — measuring 7.87 mm [0.31"] width, 12.20 mm [0.48"] height, 23.37 mm [0.92"] length, and weighing only 0.16 oz (4.5g).This valve is ideal for portable applications with limited space and power (power requirement from 0.5W to 1W). The X-Valve was designed to reduce system size and weight while providing pneumatic solutions in one package. This valve includes various mounting options available to ensure compatibility with any point-of-care system. The X-Valve is designed for direct tubing or manifold mounting, and can even be placed directly on a PCB. These options allow for mounting in tight limited space and numerous valves to be mounted together.
The demand for more point-of-care testing has driven medical device manufacturers to design smaller components and devices with the capability to replace traditional in-vitro diagnostics systems. The advancements in molecular diagnostics and miniaturization will continue to change the industry in the future. These changes will make testing more convenient and generate immediate results for patients and physicians; this will decrease the cost of care and increase early detection to improve patient outcomes. Point of care testing is one of the most promising solutions to serve an expanding population by increased patient access, improved patient outcomes with early detection, lower total costs and overall improving the lives of patients.
These are only a few examples of Parker Precision Fluidics pumps and valves that are offered for Point of Care Testing devices. Follow this link to view more Parker Precision Fluidics point of care testing solutions.
This post was contributed by Don McNeil, Strategic Marketing Manager, Parker Precision Fluidics.
Our applications engineering team is always available to provide recommendations and customize equipment to customer specifications.
To learn more, visit Parker Hannifin’s Precision Fluidics Division or call 603-595-1500 to speak with an engineer.
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