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27 Jul 2022

How to Interpret and Understand Your Certificate of Analysis

At PSI Labs, we test cannabis flower and products for licensed cultivators, processors and manufacturers; we also provide testing services for end consumers, including patients and caregivers. When the testing is complete, our clients receive an electronic Certificate of Analysis (COA). This document contains summaries of all requested tests and the data resulting from our laboratory  analyses of the provided sample. 

For cultivators and manufacturers, COAs are a record of their products’ quality and safety compliance measures, and can be used as part of the company’s internal quality management system, for state required safety validation, and for promoting access to information for end consumers.

Our goal at PSI Labs is to present each sample’s data in a clear and easy-to-understand format  that our clients can use effectively and with confidence. The PSI Labs COA is transparent and comprehensive, with disclosure of important laboratory information, equipment used in conducting the analysis and reference to the laboratory’s state-approved SOP.

Here’s a breakdown of how to best understand a COA and get the most from your cannabis testing data.

What’s in a Cannabis Certificate of Analysis?

At the top of the COA sits the header. Details about the lab doing the testing, the licensee or individual submitting the product for testing , along with the production batch or lot number, are listed here. In the case of a sample submitted by an individual consumer, patient or caregiver, the submitter’s name is listed, along with the type of product tested.

For commercial products, the name of the product brand should be able to be cross-referenced with the product packaging. In addition to the name, the unique Metrc batch ID listed on the COA will also match the unique Metrc ID listed on the product packaging.

Next up is the summary section of the COA. It contains information such as total cannabinoids in the sample as well as safety results for contaminants such as residual solvents, heavy metals and pathogenic microbiology.

Potency—cannabinoid content—is the first item detailed in the testing summary. These compounds are considered the crucial components in the sample. Results are reported in milligrams per gram (mg/g), which indicates how many milligrams of each particular cannabinoid and terpene are in a gram of the product being tested. If the tested product is an oil or other liquid, results are listed in milligrams per milliliter (mg/ml).

Another way of looking at these results is via the percentage column. This column converts the concentration of each cannabinoid and terpene from mg/g or mg/ml to a percentage of the overall weight or volume of the product, respectively. For example, when purchasing cannabis flower we typically see the Total THC reported as a percent (such as 22.5%) and not as a measure such as 225 mg/g. Any column fields that are blank or state “ND” (not detected) indicate that there were no statistically significant levels of the compound.

Limit of Detection (LOD) and Limit of Quantitation (LOQ) are also values listed for all the chemical tests on the COA. LOD is the smallest concentration that can be distinguished from zero and LOQ is the smallest concentration that can be quantified with acceptable repeatability and accuracy.

PSI Labs is licensed to conduct cannabis testing in California and Michigan and adheres to the requirements set by each state regulatory authority. The PSI Labs potency testing profile includes the following:


  • Cannabidivarin (CBDV)

  • Cannabidivarin acid (CBDVa)*

  • Cannabigerol (CBG) and Cannabigerol acid (CBGa)

  • Tetrahydrocannabivarin (THCV) and Tetrahydrocannabivarin acid (THCVa)

  • Hexahydrocannabinol (HHC)*

  • Tetrahydrocannabinol (THC-O)*

  • exo-Tetrahydrocannabinol (EXO-THC)*

  • Delta-10 THC-R, R*

  • Delta-10 THC-R, S*

*Exclusively available at PSI Labs - CA


  • 3-Carene

  • α-Bisabolol

  • α-Humulene

  • α-Terpinene

  • β-Ocimene

  • β-Pinene

  • Camphene

  • Caryophyllene Oxide

  • cis-Nerolidol

  • Eucalyptol

  • γ-Terpinene

  • Geraniol

  • Guaiol

  • Isopulegol

  • Linalool

  • Ocimene

  • p-Cymene

  • Terpinolene

  • trans-Nerolidol

Testing for Cannabis Product Safety

Testing for potentially dangerous contaminants is a critical part of any state-mandated testing protocol. Requisite contaminant testing is determined by the governing body in the state in which the lab operates.

Cannabis product safety testing typically includes pesticides, heavy metals, microbial contamination, mycotoxins and residual solvents. Some of these substances can cause illness or even death depending on the amount consumed.

This section of the COA has a column on the far right indicating whether the sample passed or failed the state’s established limits. All of the measured results are indicated in the table beginning with the Limit column that lists the safe allowable limit for each compound according to the state in which the product was tested. The form of measurement in this section of the COA is parts per million (ppm). One ppm equals one mg/kg (milligram per kilogram).

At the bottom of the COA is the footer. It should not be overlooked because it lists the standard operating procedure (SOP) used to conduct the analyses, along with the signature of the lab’s director and accompanying ISO-17025 accreditation and state licenses.

Contact us to learn more about PSI Labs’ cannabis testing procedures.


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