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Pushing PCR "Out the Door"
Category: Biological Warfare
The Department of Defense is investing millions of dollars into rapid pathogen identification for military defense and population safety concerns. The world of diagnostics and environmental testing is benefiting from this investment because technology is being used for routine purposes and not just for defense.
For example, vast changes are being seen in the food testing industry. Traditional testing continues after food products are shipped for consumption. If a problem is found or a pathogen identified, massive recalls are performed costing money and time as well as spreading fear across the population. Newer rapid molecular techniques are able to give results in less than an hour and allow food products to be shipped after all safety and quality testing is completed. Such testing techniques are also causing a revolution in quality testing in the pharmaceutical and cosmetic industry for the same reasons.
There are many types of thermocycler devices used to drive the Polymerase Chain Reaction (PCR) chemistries. Reference and clinical laboratories traditionally use non-portable, rather large instruments that remain stationary and tend to be higher sample throughput devices, for example, the Roche LightCycler(r). The next smaller size machine is considered man-portable. Systems such as the R.A.P.I.D(r) System are examples of a man-portable system.
The R.A.P.I.D is designed to be backpack transportable and easy to move. Primarily for military and first responders, the system is set up beside an incident or can be moved from test site to test site with relative ease. However, in practice, samples are brought to a central test site where a R.A.P.I.D. instrument is located. Lastly is the newest family of PCR thermocyclers, the handhelds. The RAZOR(tm) Instrument, weighing only 9.1 lbs (4.1 kg), can be carried by hand and used on-site to test samples.
Testing the sample where it is collected has practical advantages; such as sample-handling timesavings, reduction in chain-of-custody risk and most importantly, increasing speed-to-results. It is important for results from portable systems to maintain the same quality control standards of fixed assets. Moving diagnostics closer to the scene of a potential biologic threat increases response time and lowers the chance of spreading a contagion. Giving those responsible with scene assessment a better tool increases their operational capability and lowers the overall cost of response to such incidents.
No longer is laboratory equipment being adapted to the field, but field equipment is being developed using technologies once thought only applicable in the lab setting, state-of-the-art technology is now field applicable. This increases the effectiveness of those first on the scene and of field soldiers in detecting and mitigating the effects of BW agents. With advancements in chemistry solutions, quality results are not just found at reference laboratories, they are found across the spectrum of testing applications.
As mentioned earlier, the thermocycler drives the chemistry. Result specificity and sensitivity-the most important aspect of quality results-are the outcome of "good" chemistry. Advancements in chemistry have drastically reduced the logistics portion of field-testing. Freeze-drying or lyophilizing reagents reduces time-to-results and drastically improves test results by the elimination of excessive pipetting or measuring.
It also allows non-traditional testers such as first responders and other non-laboratory personnel the ability to get valid results quickly. Reagents for the RAZOR are freeze-dried in plastic PathFinder(tm) pouches, which provide increased stability. Reagents can be stored at room temperature and are packaged for rugged shipment. Each sample pouch contains a sampling kit that includes all of the necessary items to perform an analysis of potential class A bio-threats.
When preparing the test samples, the liquefied sample is automatically drawn from a syringe by the vacuum in the pouch, which eliminates the need for any measurement or pipetting by the user. This format can also be adjusted-one sample can be tested against multiple pathogens or multiple samples can be tested against a single target in the 12 lanes of the pouch. The freeze-dried reagents are the same as those used on the extensively deployed R.A.P.I.D. system.
Dependability of reagents, regardless of what environment they are used in is another advantage of freeze-dried assays. Whether testing is done in an air conditioned lab, a field tent in the middle of the dessert or in a moving response vehicle, reagents need to produce the same results. Another key aspect of freeze-dried reagents is fiscal savings. Being able to buy reagents in large lot sizes and store them without refrigeration or other special conditions brings down test costs without risking the quality of results. Systems such as the R.A.P.I.D. have many different validated assays ready for field use. By developing new assays, the utility of the system increases dramatically. Agencies don't want just an "Anthrax" tester, multiple use systems are in higher demand because of their versatility for different situations.
Applications of molecular techniques are as varied as the users themselves. Currently, system applications range from strict research uses in a pristine laboratory to roadside use by milk inspectors for the United States Department of Agriculture (USDA). Creative usage requires technology to be smarter, easier-to-use and more cost effective. PCR and molecular biology continue to be "pushed" forward, getting decision makers needed data to make accurate and meaningful operational decisions.