Definition - What does invalid test result mean?
An invalid test result in drug testing is a test result that does not have a necissary degree of confidence or is otherwise believed to be innacurate. Usually this occurs when a biological sample that has been submitted for testing does not meet the specified criteria of an acceptable sample at the time of testing. If the correct criteria are not met or the sample appears to have been tampered with, it would be documented as an invalid test result. Problems in chain of custody or equipment could also result in an invalid test result in some cases.
SureHire explains invalid test result
If a sample submitted for drug testing shows signs of tampering or fails a test to ensure the validity of the sample then the drug test can be declared invalid. For example, if a urine sample has a Ph out of normal levels or too high of a water content, it can be ruled a bad sample and the test considered invalid. Likewise, should some other factor influence a drug test in a negative way, such as chain of custody issues, a damaged shipment, or a machine failure, a test may be declared invalid. In most cases a retest will occur but the Medical Review Officer will consult with DOT regulations (where applicable) and company policy to make a final determination.