FOI Request - Cross-Reactivity and False Positive Safeguards in Drug Testing

Request 101004025989

I am requesting the following additional information under the Freedom of Information Act 2000:

1. Is your authority (and/or its commissioned substance misuse service
provider) aware of the cross-reactivity risks identified above? Has any assessment been made of the likelihood of false positive results from lawful sources when using immunoassay screening?

2. Does the applicable drug and alcohol testing policy require that all positive screening results are confirmed by a second, independent analytical method — specifically GC-MS or LC-MS/MS — before any disciplinary, safeguarding, or service-access decision is made?

3. If confirmatory testing is not routinely carried out, on what basis are positive screening results treated as definitive?

4. Has your authority (and/or its provider) received any complaints, grievances, or representations from individuals who attributed a positive drug test result to any of the lawful sources listed above?
If so, how many in the last three years, and what was the outcome?

5. What guidance, if any, has been issued to staff involved in drug testing about the possibility of false positives from lawful substances, and the appropriate steps to take before acting on a screening result?