|
Technical Bulletin: The Use of Dry Reagent Technology Test Strips For Chemical Analysis in Dialysis Water Treatment Applications
|
Dan Morris, PhD, and Joe D. Sweazy - 2002
|
Accurate chemical analysis of the solutions that are used in the dialysis process is essential. A method that is increasingly used for analyzing these solutions is the test strip. Test strips utilize a dry reagent technology that eliminates the need for reagent solutions and tablets.
The reagents are incorporated into the test strip to provide a convenient means of measuring concentrations of various chemical parameters. This method has been practiced for years, and test strips continue to improve and become more useful for a wide range of applications. Benefits include convenience, independence of user technique, and accuracy.
Test Strips' History
Test strips have been utilized in the medical industry for almost 40 years. The first major breakthrough to convenient analysis in test strip format came with the introduction of CLINISTIX® (Bayer Corporation), the first dip-and-read urine test introduced by Miles Laboratories in the late 1950s. This was the first application for modern test strips in the medical industry. This test measured the glucose level in urine.
Shortly after the introduction of test strips for urinalysis came the introduction of test strips for measurement of serum, and subsequently, in the early 1970s, test strips for measurement of chemical parameters in blood. The real benefit of this testing method is that it was so easy and inexpensive to use that it moved testing beyond the doctor’s office or clinical laboratory into the home as well.
Today test strips are used in many applications, including dialysis. They can be used to test feed water, rinse water, water in holding tanks, and practically every other solution that requires testing in the dialysis process. These test strips are gaining in popularity among doctors and technicians for two main reasons:
(1) Ease of use; and
(2) Accuracy.
Ease of Use
Test strips are so easy to use that elementary school students have been known to use them to test water quality for science fair projects. It is just as easy for doctors and technicians to use the strips.
Reagent test strips are supplied in a ready-to-use form. Most test strips rely on a colorimetric reaction to indicate the concentration of the chemical parameter that is being measured. When placed in contact with the solution being measured, the test area changes color relative to the amount of the specific chemical being tested.
While the technique for activating the tests will vary, most test strips require a simple dip-and-read activation. In addition, the tests are completed very quickly, and the results from most tests are obtained within 15-30 seconds. The results are obtained by comparing the color formed on the strip to a color chart. In fact, several tests are often combined on one test strip.
When testing is complete, the test strips are simply discarded into the nearest trash can. There is no messy clean up, rinsing of comparators or test tubes, or worrying about proper waste disposal. Test strips are not only easy and convenient to use--they also provide accurate results.
Accuracy
The accuracy and reliability of test strips have led to their widespread use for analysis of blood and urine. They are as accurate as any liquid or tablet test kits or electronic device. The accuracy and convenience are demonstrated by their continued use by persons with diabetes who monitor their blood sugar levels at home. They require accuracy so that patients’health will not be in jeopardy.
Visually-read test strips require that the color distinction between reference color blocks is obvious to a user with normal color acuity. This often means that all of the concentration increments available with other methods are not practical for visually-read test strips. However, the levels provided for test strips allow the user to make meaningful decisions on treatment options.
Several factors may affect the accuracy of test strips. Here are some tips to ensure accurate results:- Store the strips in a low humidity environment, typically at standard temperatures with the cap sealed tightly to preserve the reactivity of the strips;
- Handle the strips with dry fingers to avoid introducing moisture into the bottle that would react the test strips prematurely; and
- Know the performance characteristics and limitations of the test strips. This information is generally provided with every complete kit.
Conclusion
The one thing that cannot be disputed is that test strips are among the easiest and fastest methods for testing solutions in the medical industry. They can also be as accurate as any other method.
As new and improved tests are introduced, test strips will undoubtedly continue to gain popularity among medical professionals.
Dan Morris, PhD, is director of Technology, Environmental Test Systems (ETS, manufacturer of SteriChek reagent test strips), Elkhart, IN. Joe Sweazy is Technical Service associate at ETS.
|
Read another article
|
|
|
