How Long Does Codeine Stay in Blood?
Evidence-based answer reviewed against SAMHSA cutoffs and FDA assay documentation · Updated August 2026
Quick answer: Most people clear Codeine from blood within ~12–24 hours of last use — heavy or daily use stretches that window substantially. Covered by the standard opiate strip: 2,000 ng/mL morphine/codeine.
Codeine detection windows by test type
Each specimen tells a different story because each samples different biology:
| Test type | Typical Codeine detection window |
|---|---|
| Urine | any: 1–3 days (codeine) |
| Saliva (Mouth Swab) | any: 1–2 days |
| Hair Follicles | up to 90 days |
| Blood | any: ~12–24 hours |
('Blood testing measures ACTIVE circulation — closest proxy to impairment, shortest windows (hours-to-a-couple-days). Hospitals order it clinically; courts order it post-accident (DUI contexts); employers rarely bother given logistics and cost.',)
Why detection works this way
Lean's codeine lands squarely on the classic opiate panel — this is one street drug standard testing catches without any expansion.
Promethazine itself isn't screened, but it can flag old-generation amphetamine screens as a false positive; confirmation sorts it out.
Prescription codeine (codeine-acetaminophen tablets, cough syrup) verifies via MRO like any opioid script.
Testing cutoffs in plain language
Covered by the standard opiate strip: 2,000 ng/mL morphine/codeine. A specimen under the initial cutoff reports negative without further work; a screen above cutoff gets confirmed by mass spectrometry before anyone sees a positive.
Planning ahead? Our at-home drug test guide covers retail kits that mirror lab screens.
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Does Promethazine Show up on a Drug Test?
Yes — Codeine appears on standard drug panels. Full guide →
Can Codeine Cause a False Positive Drug Test?
Can Codeine trigger a false positive? Cross-reactivity evidence, confirmation testing, and how to clear your name with the MRO. Full guide →
How Long Does Codeine Show up in a Drug Test?
How long Codeine stays detectable in your system (all test types) — urine, hair, saliva & blood windows explained with cutoffs. Full guide →
How Long Does Codeine Stay in Urine Drug Test?
How long Codeine stays detectable in urine — urine, hair, saliva & blood windows explained with cutoffs. Full guide →
Do prescriptions count against me?
No — verified prescriptions report as negative through the Medical Review Officer. Declare medications at collection and answer the follow-up call.
Related guides
Sources & further reading
- SAMHSA — Mandatory Guidelines for Federal Workplace Drug Testing Programs (cutoffs, MRO process)
- DOT — 49 CFR Part 40 procedures for transportation workplace testing
- Brahm NC et al., Mayo Clinic Proceedings 2008;83(1):66–76 — false-positive cross-reactivity reference
- FDA — drug-of-abuse test device labeling (detection window conventions)