what is a negative drug test result
1 Positive test results also can mean that the amount of a substance being tested for is higher or lower than normal. 2  A negative test result means that the substance or condition being tested for was not found. false-negative test result may suggest that a person does not have a disease or condition being tested for when he or she does have it. For example, a false-negative pregnancy test result would be one that does not detect the substance that confirms pregnancy, when the woman really is pregnant.