False-Positive Postmortem EMIT Drugs-of-Abuse Assay due to Lactate Dehydrogenase and Lactate in Urine

Three cases of multiple false-positive drug tests are described. Postmortem urine specimens were screened using the enzyme-multiplied immunoassay technique. All patients had proteinuria and lactic aciduria. These false-positive reactions were due to the presence of lactate dehydrogenase (LDH), lactic acid, and protein. This finding was confirmed by creating a multiple false-positive sample with a solution of LDH and lactate in 5% bovine serum albumin at pH 6.