ORS § 830.525
In addition to chemical tests of the breath, blood or urine administered under ORS 830.505 and 830.520, upon the request of a peace officer, a person shall be permitted upon request, at the person's own expense, reasonable opportunity to have any licensed physician, licensed professional nurse or qualified technician, chemist or other qualified person of the person's own choosing administer a chemical test or tests of the person's breath or blood for the purpose of determining the alcoholic content of the person's blood or a chemical test or tests of the person's blood or urine, or both, for the purpose of determining the presence of cannabis, psilocybin, an inhalant or a controlled substance in the person. The failure or inability to obtain such a test or tests by a person shall not preclude the admission of evidence relating to a test or tests taken upon the request of a peace officer.
ORS 830.525