Final answer:
Alcohol pads are not used when collecting a blood alcohol specimen because they can interfere with the accuracy of the test by contaminating the sample and potentially altering the blood alcohol concentration.
Step-by-step explanation:
When collecting a blood alcohol specimen, alcohol pads are not used because they can interfere with the accuracy of the test. This is because the alcohol from the pad could contaminate the sample by leaving a residue on the skin that could potentially be picked up by the needle and mix with the blood sample. This contamination could falsely elevate the blood alcohol concentration (BAC), leading to inaccurate results. Because of this risk, alternative disinfectants that do not contain alcohol, such as chlorhexidine or iodine, are typically used for cleaning the site before a blood alcohol test.