If you are given a breath test pursuant to your Chester County DUI, your Chester County DUI lawyer should be requesting discovery on the case. As part of the discovery, your attorney should receive the "Breathtesting Device Calibration" certificate. You will review the accuracy as outlined in 75 Pa. C.S. 1547 (c). The calibration test will provide the test results over a series of tests, including the "constant" variable of .05%, .10%, and .15%. The machine will run a test on these constants and the average deviation will result. You will also get a print out of the results. In addition, you will receive a "Certificate of Analysis" of the solution used on the "constant" simulation. This is normally provided by Guth Laboratories, Inc. and will include the Lot Number, and the percent of ethyl alcohol by w/vol as analyzed by gas chromatography.