Other causes include: 1  A fall against a hard surface in the seated position, such as a fall from a horse. 2  A direct blow to the coccyx, such as in contact sports.  Straining or dislocating the coccyx. This can happen due to poor posture while driving, or repetitive injury from sports such as rowing or cycling.
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.
Blood tests are the least used for pre-employment drug screens because drugs are non-detectable in the blood stream after 48 hours. Labs generally report blood test results as quickly as they report urine test results.For most labs, that means results are available 24 hours after the specimen is tested, or 48 hours or more when the specimen must be delivered to a lab.hen drug screens return a negative result, the applicant is not tested again. The results of a negative test are usually available to employers within three business days after testing is completed. A positive test generally requires additional testing, and will thus take more time.