Musk's post to social media is the latest in a series relating to his alleged drug use, following a report in The New York Times.

Hair follicle drug tests involve removing a small hair sample for laboratory testing. Results can show if a person has been using certain drugs or prescription medications in the previous 3 months.

A negative result can be determined within 24 hours of hair removal. A test called ELISA is used as a screening test. This test determines if the hair sample is negative for drug use. A negative ...

A 10-panel drug test ... give the sample to the test administrator. When they receive the sample, the lab will test the urine for the 10 different drugs. Some tests offer onsite results that ...