# Lab shopping

> Lab shopping is the practice of choosing testing labs because they report higher potency or more passing results, rather than because they are most accurate.

- Canonical: https://genetixbay.com/knowledge/glossary/lab-shopping.html
- Also written: lab-shopping, shopping for labs, potency shopping, lab hopping, testing shopping
- Glossary category: Lab testing · Evidence: Supported
- Status: Draft: awaiting expert review · Updated: 2026-10-31
- Licence: CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0/), attribute "GenetixBay cannabis glossary"

Lab shopping happens when producers send samples to the labs that return the highest [THC](https://genetixbay.com/knowledge/glossary/thc.md) numbers or the fewest contaminant failures. Labs compete for clients, and in a market where higher THC sells for more, there is pressure to deliver "good" numbers. The practice, not any individual lab, is the problem GenetixBay calls out.

## In practice

Jikomes and Zoorob (2018) analysed Washington State's regulatory data and found that reported THC differed systematically between testing facilities, consistent with some labs reporting higher potency than others. Schwabe et al. (2023) bought retail flower and found that most samples tested below their label claims, many by a wide margin. A Colorado study (Giordano et al. 2025) found [label accuracy](https://genetixbay.com/knowledge/glossary/label-inflation.md) varied with product type. Regulators in several states have responded with standardised methods, audits and recalls.

## Don't confuse with

- **Measurement uncertainty**: honest random variation of a point or two, not a consistent upward bias.
- **Getting a second opinion**: retesting at an independent [accredited lab](https://genetixbay.com/knowledge/glossary/iso-17025.md) to check a result is good practice.

## Myth check

House position: lab shopping and label inflation are real and documented. Criticise the practice, never named businesses. See [buyer beware](https://genetixbay.com/knowledge/basics/buyer-beware-label-claims.md) and [Mythbusters](https://genetixbay.com/knowledge/mythbusters.md).

## Related terms

[Label inflation](https://genetixbay.com/knowledge/glossary/label-inflation.md), [Potency ceiling](https://genetixbay.com/knowledge/glossary/potency-ceiling.md), [COA](https://genetixbay.com/knowledge/glossary/coa.md), [Proficiency testing](https://genetixbay.com/knowledge/glossary/proficiency-testing.md), [Measurement uncertainty](https://genetixbay.com/knowledge/glossary/measurement-uncertainty.md)

## Read more

- [Buyer beware: potency labels, strain names and other claims that don't hold up](https://genetixbay.com/knowledge/basics/buyer-beware-label-claims.md)

## Sources

1. Jikomes N, Zoorob M. 2018. The cannabinoid content of legal cannabis in Washington State varies systematically across testing facilities and popular consumer products. Scientific Reports 8:4519. https://doi.org/10.1038/s41598-018-22755-2
2. Schwabe AL, Johnson V, Harrelson J, McGlaughlin ME. 2023. Uncomfortably high: Testing reveals inflated THC potency on retail Cannabis labels. PLOS ONE 18(4):e0282396. https://doi.org/10.1371/journal.pone.0282396
3. Giordano G, et al. 2025. Label accuracy of retail cannabis flower and concentrates in Colorado. Scientific Reports. https://www.nature.com/articles/s41598-025-03854-3