Cannabis Condensate Mass Varied Within and Across Participants

The condensate study reported both variation across samples and variation within each participant. A nonsignificant difference between average collection masses did not establish that every person supplied an equivalent sample.

The paper used more than one summary

All collected condensate samples exceeded 0.5 g. The coefficient of variation across samples was approximately 28%, while most participants’ samples were within 20% of their own average. Two participants were exceptions to that within-person pattern. Average condensate mass did not significantly differ across the sampling times.

Group averages can conceal individual variation

An overall comparison of collection times asks a different question from consistency within one person. Similar group means can coexist with individual differences, and a person’s deviation from their own mean need not match the pooled coefficient of variation. These measures should not be treated as interchangeable estimates of reliability.

Collection consistency does not establish diagnostic performance

These were collection-mass observations in a small human feasibility study, not direct measurements of aerosol production or functional impairment. Water recovery, cannabinoid recovery and biological exposure remain separate quantities. The study did not establish that adjusting a THC result by collected mass produces a validated impairment assessment.

For interpretation of a condensate result, retain the individual collection mass and protocol alongside the chemical result. A group-level null comparison cannot substitute for information about the particular sample. It also does not validate another device, breathing maneuver or collection duration.

Related analysis: the condensate proof-of-concept study.

Research cited

Berry and colleagues (2024). Cannabinoids detected in exhaled breath condensate after cannabis use. DOI: 10.1088/1752-7163/ad6347.