Compared to the more traditional cannabis flower, cannabis concentrate products, such as extracts, tinctures, edibles, waxes, and oils are becoming the most commonly used cannabis products that are legally manufactured for both medicinal and recreational purposes. Most concentrates are extracted using a solvent such as supercritical CO2, butane, propane, other hydrocarbons, water, or alcohol. These solvents are used to extract out the cannabinoids and terpenes from the plant material. In some cases, the solvent and impurities from the solvent remain in the extracted material. These are called residual solvents and are the byproducts of the extraction process. In some cases, these impurities can be toxic, which is why residual solvent analysis is a critical element of cannabis testing. The method of choice for measuring residual solvents is headspace (HS) gas chromatography (GC) coupled with mass spectrometry (MS) detection, so false positives are not reported. To further validate the performance of this method for the industry, The Emerald Test Proficiency Test (PT) for Potency was conducted. The Emerald Test™ is an Inter-Laboratory Comparison and Proficiency Test (ILC/PT) program for cannabis testing labs. The results from the PT inter-laboratory samples passed; therefore, the method meets inter-laboratory reproducibility and accuracy.