Guided case: resolve the opiate screen

An outpatient pain-management urine specimen collected at a scheduled visit has an opiate immunoassay positive using a local 300 ng/mL morphine-equivalent cutoff, not a forensic collection. The patient reports hydrocodone/acetaminophen twice daily, with the last dose about 14 hours before collection.

Reflex LC-MS/MS reports hydrocodone 850 ng/mL, norhydrocodone 210 ng/mL, and hydromorphone 40 ng/mL. Hydrocodone identification requires a quantifier transition, qualifier transition with accepted ion ratio, retention-time match, and stable-isotope internal standard; a single peak at one retention time is not definitive identification.

Norhydrocodone with hydrocodone is consistent with hydrocodone metabolism, and the small hydromorphone concentration can be a minor metabolic finding. Absence of 6-monoacetylmorphine argues against recent heroin exposure within that analyte's detection window, but its short window prevents a broader exclusion. The definitive pattern supports language such as consistent with prescribed hydrocodone therapy.

Urine creatinine is 62 mg/dL and specific gravity is 1.018. These values do not meet the federal dilute or substituted criteria stated in the table. They do not turn urine concentrations into a dose measurement.

Use a metabolite pattern to explain a result, then stop at the boundary of what that pattern supports. Compare the pattern with the method limits. Do not convert it into an adherence clock.