The latest incident comes after Delta on Sept. 29 reinstated five workers dismissed for failing the validity tests. It cited the possibility of improper processing at LabOne, the company hired to evaluate the tests. Delta said then it would switch laboratories and would not dismiss any workers failing validity tests processed by LabOne. Since questions surrounding LabOne's method's surfaced, Dr. Michael Peat, president of its substance-abuse testing unit, has said he would leave the company for personal reasons. Delta's pilots union, which opposes validity testing, has said LabOne incorrectly reported the level of creatinine, a substance found in urine and used to assess the sample.
Airlines use validity tests to ensure that a urine sample comes from the employee tested.
Many flight attendants who have failed are petite women who eat little meat and drink several liters of water a day, which the union argues can skew the test. Leaders at Delta's pilots union also question the science behind the test and say that it doesn't accurately assess whether a urine sample is genuine. Michelle Nelson, the flight attendant placed on sick leave, said she expected to hear from the airline on Friday about the status of her employment. Delta declined to comment on the matter.