Oral Fluid DOA Test Kit E&I Exempt for Workplace Employment and Insurance Use Oral fluid DOA test kits are able to be administered under close supervision which makes it hard to attempt any type of concealed tampering. Saliva tests enable a screening on a very short detection time period. They are designed to tell if someone has recently used a substance, but not whether that person uses substances more or less regularly. However, urine tests allow for a background screening, which detects substance use over a period of several days or even weeks.