These are primarily errors ofomission or of additional unwarranted laboratory testing, such as failing to make apour off for an ordered test, entering orders for tests which were not requested,failing to enter orders for tests which were requested, or excessive delay inprocessing resulting in the test missing the scheduled run. These includemixing up samples from different patients, mixing up two different specimensfrom the same patient, using the wrong specimen additive, and similar mistakes,as well as errors which may require a patient to repeat an invasive diagnosticprocedure (e.g., failure to properly preserve or store a CSF which results in thepatient undergoing another spinal tap).