Can a cell phone transmission cause a false breath reading?
In this experiment a Nokia cell phone was transmitting close to an Intoxilyzer® 5000 evidentiary breath testing instrument. The subject who had a true BAC of 000 blew 10, 34, and 33 mg / 100 mls, all results in good agreement (within 20 mg /100 mls of each other truncated).
Cell phones should not be used in a police station breath room because they can cause RFI interference to the breath analysis without triggering the RFI detection system on the evidentiary breath equipment. Just because an instrument does not flag "RFI Inhibit" or a similar warning does not prove there was no dangerous RFI in the room.
Cell phones can produce false or exaggerated readings during both subject tests and calibration checks. They also should not be used during diagnostics, reference checks, or air blanks.
Cell phone RFI can also cause bizarre other effects such as false error messages of invalid sample, range exceeded, unstable reference, and ambient fail.