Six-Month Frozen Pad Stability Did Not Mean Six-Month Breath Detection

The six-month experiment tested cannabinoids stored on fortified collection pads after preparation for laboratory evaluation. It did not test how long a living person continues to exhale cannabinoids after use.

The study followed a collected material

Fortified pads at low and high control concentrations were stored at −20°C. After six months, the tested cannabinoids showed losses of approximately 10.8–18.2% relative to target controls. Separate checks addressed short room-temperature storage, freeze-thaw cycles and prepared-extract autosampler conditions.

Preservation and biological persistence are different

The frozen-pad result addresses whether a collected analyte can remain measurable during storage. A detection window in a person depends on exposure, physiology, sampling and assay sensitivity. The presence of a compound on a stored pad months later says nothing by itself about continued elimination from the participant over those months.

Apply the matching validation

A case review should identify the specimen stage, pad, container, temperature and elapsed time. Fortified controls do not automatically reproduce every authentic specimen or shipping condition. These data neither prove that every old pad remained unchanged nor provide a universal correction percentage. They support the particular storage experiment while leaving impairment and timing-of-use conclusions to separate evidence.

Related analysis: actual breath-collection timing.

Research cited

Himes and colleagues (2013). Cannabinoids in Exhaled Breath following Controlled Administration of Smoked Cannabis. DOI: 10.1373/clinchem.2013.207407.