Metabolites, Cutoffs, and Validity

Morphine can arise from morphine administration, codeine metabolism, poppy food exposure, or heroin use recent enough that the heroin marker has cleared. When 6-acetylmorphine is present, it is a specific urinary marker of heroin. Morphine and codeine alone do not separate these explanations. A pattern must be described as compatible or incompatible, not as proof of a behavior.

A cutoff is a decision threshold for that method, not a population reference interval and not a measure of impairment. In covered federal testing, codeine and morphine initial testing uses 2,000 ng/mL and confirmatory cutoffs differ by analyte. A typical clinical opiate immunoassay may use a lower cutoff, often around 300 ng/mL. Do not apply the federal numbers to a clinical result unless the program is covered and the current rules apply.

Specimen validity testing can include creatinine, specific gravity, pH, and oxidant testing where applicable. Under federal criteria, dilute, substituted, adulterated, and invalid categories use defined measurements, but clinical laboratories establish and report validity findings under local policy. An abnormal validity measure changes confidence in the specimen, not the analytical target list. Document the validity findings and use the laboratory's policy before deciding whether recollection is warranted.