Point-of-care instrumentation grows with increased clinical need.The U.S. is the world's largest market for diagnostic testing Diagnostic testing Testing performed to determine if someone is affected with a particular disease. Mentioned in: Von Willebrand Disease , and point-of-care testing point-of-care testing Lab medicine The analysis of clinical specimens as close as possible to the Pt, including bedside, ward–unit, or 'stat' regional response labs that service specified areas–eg, the ER or ICU (POCT POCT Point of care testing, see there ) is one of the most active divisions of the diagnostic industry. That's not a surprise considering the increased demand for near-patient testing over the past few years. In fact, POCT revenue is expected to grow at a 13.8-percent average annual growth rate through 2010. The trend toward more POCT has been driven by the quick diagnostic benefits these instruments offer, in addition to the nationwide effort to improve patient care and time to treatment. Other factors include cost containment cost containment, n the features of a dental benefits program or of the administration of the program designed to reduce or eliminate certain charges to the plan. , the aging population, increasing incidence of certain diseases and technological advances. So, more tests are being administered at physician's offices, outpatient clinics, emergency rooms and intensive care units than ever before. Considerations for POCT A good point-of-care device needs to meet certain clinical criteria. Advanced POCT instruments combine selected chemistry, hematology and hemostasis hemostasis /he·mo·sta·sis/ (he?mo-sta´sis) (he-mos´tah-sis) 1. the arrest of bleeding by the physiological properties of vasoconstriction and coagulation or by surgical means. 2. parameters to provide the most accurate and reliable results. Respiratory therapists, lab technicians and other clinicians must consider the following: accuracy of results, reliability, reproducibility, ease of use, time for instrument control and setup, portability and test availability (for example, blood gas, electrolytes, glucose, measured tHb). Because all POCT must be covered by a hospital's laboratory license, laboratory administrators need to consider other various points. * Does the instrument use unique usernames and passwords? * Does the device have lockout lockout, intentional closing up of a company, factory, or shop by an employer to prevent employees from working during a strike or labor dispute. The term lockout capabilities? * Will it interface with the main lab computers? * Does it have electronic controls? * How does the cost compare to alternative instruments? Additionally, POCT devices should allow clinicians to remotely download quality control and patient result data by way of a network connection. Portable bench-top tests While the focus for the past few years has been incorporating testing capabilities into handheld instruments, some manufacturers have moved to downsizing (1) Converting mainframe and mini-based systems to client/server LANs. (2) To reduce equipment and associated costs by switching to a less-expensive system. (jargon) downsizing their bench-top blood gas analyzers into portable units. These easily portable instruments bring the power of an in-laboratory instrument to the bedside. These models offer most of the same critical tests as their larger counterparts. Tests include total hemoglobin (tHb), hemoglobin oxygen saturation oxygen saturation sO2 The O2 concentration of blood expressed as a ratio of its total O2-carrying capacity; the OS is a measure of the utilization of O2 transport capacity; sO2 , ionized i·on·ize tr. & intr.v. i·on·ized, i·on·iz·ing, i·on·iz·es To convert or be converted totally or partially into ions. i calcium, glucose, hematocrit Hematocrit Definition The hematocrit measures how much space in the blood is occupied by red blood cells. It is useful when evaluating a person for anemia. Purpose Blood is made up of red and white blood cells, and plasma. and electrolytes, to name a few. And requiring sample sizes in ranges of 75 [micro]L to 120 [micro]L portable analyzers are ideal for a variety of patients across the continuum of care. One such portable blood gas analyzer uses patented optical fluorescence technology. This design utilizes light as a reference instead of an electrode, offering increased reliability. Optical fluorescence also means that electrodes are, in fact, eliminated. The unique design of the sensor also eliminates costly maintenance and downtime because it prevents lipid and protein buildup. Low maintenance is important when a device is constantly on the move. With that in mind, portable bench-top instruments usually incorporate some or all of the following features: * Single, self-contained reagent cartridges that minimize operator exposure to biohazards. This eliminates the need for gas tanks and reagent bottles at the bedside. * Self-cleaning sample probes that help maintain sample integrity. * Modular design In the context of systems engineering, modular design — or "modularity in design" — is an approach aiming to subdivide a system into smaller parts (modules) that can be independently created and then used in different systems to drive multiple functionalities. that simplifies access for valve and sensor replacement when required. * One-point calibration after every sample. * Automatic sample aspiration for analyzing samples from syringes and capillaries without the need for special adapters. Single-use cartridges Single-use cartridges are an important feature of some of the latest POCT devices. These cartridges are available in a variety of analyte configurations for testing flexibility. Usually these cartridges do not require refrigerated re·frig·er·ate tr.v. re·frig·er·at·ed, re·frig·er·at·ing, re·frig·er·ates 1. To cool or chill (a substance). 2. To preserve (food) by chilling. storage and are ready to be used at any time. One of the most advanced single-use cartridges contains miniaturized electrochemical electrochemical /elec·tro·chem·i·cal/ (-kem´i-k'l) pertaining to interaction or interconversion of chemical and electrical energies. e·lec·tro·chem·i·cal adj. measurement sensors and an onboard calibrant. They are part of a self-contained, portable device that can customize testing for site-specific analyte reference ranges. The instrument conducts an extensive self-check on the cartridge and sensors for enhanced quality control. This includes the following steps: * Verifying that the cartridge is warmed to 37 [+ or -] 1 [degrees]C. If this temperature is not achieved or is exceeded, an appropriate error message will be displayed and testing is prohibited. * Verifying that the card type matches the calibration code type and that the expiration date Expiration Date The day on which an options or futures contract is no longer valid and, therefore, ceases to exist. Notes: The expiration date for all listed stock options in the U.S. has not been exceeded. If an expired cartridge be inserted into the instrument, testing will be disallowed. * Sensor Checks - Many checks are made on each sensor type throughout the entire test. These tests include, but are not limited to, sensor timeouts due to unresponsive sensors, sensors that are unstable or produce values out of a reasonable range and sensors that are drifting. * Each cartridge undergoes individual calibration during pre-warm when inserted into the POCT instrument. Smartcard analysis Instead of a standard cartridge, one point-of-care blood gas analyzer utilizes smartcard technology. These test cards are single-use units identified by barcodes, and they contain a biosensor A device that detects and analyzes body movement, temperature or fluids and turns it into an electronic signal. See lab on a chip and data glove. Biosensor array, calibration solution and fluidics fluidics, branch of engineering and technology concerned with the development of equivalents of various electronic circuits using movements of fluid rather than movements of electric charge. . Another benefit is that these cards require no refrigeration refrigeration, process for drawing heat from substances to lower their temperature, often for purposes of preservation. Refrigeration in its modern, portable form also depends on insulating materials that are thin yet effective. . That means they can be stored at the bedside, in the nurse's station or wherever it's convenient. The test cards generate electrochemical assay signals and quality control signals, which are read by detectors in the POCT device. After a clinician administers a test, he or she inserts the smartcard into the reader. The device scans the card's bar code, initiates sensor calibration and provides thermal control of the assay. It also reads electrochemical signals and quality control signals from the test card and converts them to a secure wireless transmission format. A customized mobile computer can receive transmitted signals from any of the POCT instruments using the smart cards. The mobile computer associates the test results and reader ID with a patient ID, which is scanned or entered manually, to complete the test record. Clinicians can then wirelessly transmit the test information to a data management system for further compliance reporting, analysis and system management. The quality of test results from this particular POCT system are equal to or better than results generated by traditional blood gas analyzers in a hospital lab. This is because once blood is passed across biosensors on the smartcard, results reach the mobile computer in 30 seconds. Systems requiring more time between sample acquisition, sample entry and analysis can result in sample degradation and compromised results. [ILLUSTRATION OMITTED] Stephanie Richardson is a freelance medical writer in Philadelphia. |
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