Point-of-care blood analysis is aimed at providing immediate test results of a patient’s plasma. This allows the doctor to screen, diagnose and monitor the patient’s status before hospitalisation, or in emergency situations.
Point-of-care blood testing began in the mid to late 1980s, after scientists developed chemical sensors that could be used with whole blood, and compact instruments that could measure several analytes in a sample. The point-of-care analysers were developed for non-technical people in order to make the therapeutic turnaround time (TTAT) quicker. The TTAT is measured from when the test is ordered to when the physician has a hard-copy of the results. Usually the TTAT for off-site tests is between 20 minutes to one hour, and is logistically difficult, whereas point-of-care blood analysis provides results in less than five minutes.
Blood analysis devices are lightweight, battery-operated, handheld systems. They range from the size of a cordless phone to a laptop computer, and include a portable clinical analyser, disposable blood-test cartridges, and a portable or on-board printer. Most are also part of a system of data management, which allows the results of on-sight tests to be downloaded to another printer, a lab, or hospital information system. The results of blood tests can be collaborated with patient histories in real-time, which allows broader monitoring of the patient’s health. The devices measure analyte blood glucose or hemoglobin, as well as blood gas levels.
Two main blood analysis devices are called the I-STAT and the IRMA Analyser. The I-STAT requires two drops of blood on a cartridge, which is then inserted into the handheld analyser. The analyser automatically positions the blood sample over bio-sensors, and measures the electrical signals to calculate results. The IRMA Analyser requires the disposable cartridge to be inserted first, and then the injection of a sample into the cartridge. The results are also calculated using electrochemical methodologies.
Other devices include the Instrumentation Laboratory’s GEM Portable Coagulation Laboratory. This is portable, but not handheld, as it weighs about fifteen kilograms. The Nova 16 is similar in this respect, but weighs nearly 45 kilograms. It provides a core test panel, and is able to do up to 13 tests in two minutes. The Irma Trupoint tests blood, gas and electrolytes using capillary blood samples, as well as arterial and venous samples. It uses disposable cartridges, and has an on-board printer to deliver results quickly.
Point-of-care blood testing is a both fast and effective way to test patient’s plasma for irregularities on-site. The test results from handheld devices are consistent with central lab results, and the time taken to obtain them is significantly less. These tests use only a small amount of fresh blood, which can eliminate complications from using larger samples; the single-use cartridges are easily disposed of as bio-hazard. Specimen collection, storage, and transportation are complications of regular lab blood testing that are reduced through point-of-care testing. This method does not require extensive training in order for it to be used, and allows physicians to test within their own practises rather than relying on outsourcing. In the long term, this method proves to be more cost effective for both practitioner and patient than lab testing. It cuts back on personnel costs in laboratories, and the potentially high costs of hospitalisation for the patient.
There are, however, drawbacks of using the point-of-care testing method. The cost is about four to fives times that of batched testing done in central laboratories, and point-of-care users, such as physicians, ask for higher salaries than lab personnel. In general, however, these costs can be weighed against the potential costs associated with hospitalisation, and the point-of-care method ends up being significantly cheaper.