How To Read a Certificate of Analysis (COA) Part 2 (2 part series)

Our 1st "How to Read a Certificate of Analysis (CoA) Part 1" (in our 2 part series) answers what is a CoA (Certificate of Analysis) to verifying if there is actually CBD in what you’re buying, how much and how can one be sure it’s safe to use? It is also important to know that there are no other contaminants as a result of extraction or how it was grown as it could also contain residual pesticides or heavy metals which can later be absorbed by the plants and show up in your CBD product. 

In our Part 2 series, we actually break down how to read an actual CoA and what does it all mean? When looking for a product made with cannabis, it’s very important to go to reputable, licensed retailers. The reason is that only cannabis that is tested by a laboratory can be deemed safe to consume. The allowable amounts of each analyte/compound in cannabis are set by the regulating agency for each state, and by federal guidelines for hemp and hemp derived products.

COA Illustration with a coffee mug next to it and hemp leaves

Since there is not yet a testing standard, different labs can get different results on the same product and the format of the CoA could look different. Regardless, they all report on the same testing categories. Some results are formatted as an actual numerical value specified according to the analyte. Others are reported out as “ND” (not detected) if the lab doesn’t identify that particular compound or substance. On occasion, you’ll also see “NT” which means the lab did not test for that analyte or series of analytes.

You may also notice that there are columns on the report with the headers “LOD” and “LOQ.” These refer to a specific laboratory’s ability to detect and quantitate the analytes of interest, which limits are determined through testing and validation of the data. A limit of detection is the lowest quantity of a substance or analyte that can be distinguished from the absence of that substance within a stated confidence limit.

Limits of quantitation are the minimum concentration of an analyte in a specific matrix that can be reliably quantified while also meeting predefined goals for bias and imprecision. Even in the testing, there is a margin of error, and this too is taken into consideration when establishing these limits.

Take a look at the CoA below, which was done as “research and development” testing for a manufacturer, the results of which would be reported back to that manufacturer. In the case of state-mandated testing of cannabis products, this result would have necessitated that the manufacturer either destroy the product OR perform post- production processing to remove the compounds which cause the batch or product to fail. The blue numbers on the CoA are referenced below in the explanation of each section.

COA form of product with measured levels of contents


This section is a summary of all of the test results. It’s like a quick glance at the overall cleanliness of the product. It lists “PASS” or “FAIL” in each of the boxes pertaining to a particular category of testing. If there was something not tested for, this section could also contain “N/A.” Since all testing must pass in order for any cannabis product to be sold, you should not see a “fail” in any of the boxes for a legal product purchased. If any group of tests fails, the entire product fails overall.

#2 – Potency/Cannabinoids

Note that as we get into the various categories of testing, you’ll see that each “test” actually contains multiple analytes of interest. On this CoA, there are eleven cannabinoids being measured, all of which contribute to the “Total Cannabinoids” in a product, both the non-psychoactive (CBD, for example) and the psychoactive (THC) components of a product. Ideally, the reported values should coincide with the label on the product. These results are reported in milligrams per gram of product.

#3 – Terpenes/Terpenoids

These are the natural compounds found in hemp and cannabis that are responsible for each specific plants color, flavor, and smell. These are also measured in milligrams per gram of product. Each terpene is linked to particular effects, however many products do not list the terpene content on the label. As such, having a CoA to review can help you choose a product specific to what you’re seeking. For example, if you’re looking for something that is relaxing and soothing, you may want a product with a higher concentration of linolool, a terpene that is also found in lavender and is instrumental in the relaxation effect in cannabis. Information about specific terpenes and their effect can be readily found on the internet.

#4 – Mycotoxins

These are compounds produced by certain types of molds/fungi. On this California CoA, none of the compounds were detected in the sample submitted, thus resulting in a “Pass” result. Note that the result for each of the toxins is listed as “ND,” which means “Not Detected.”

#5 – Heavy Metals

Regulations have set safe limits for the levels of heavy metals that can be present in a product. The four metals California requires testing for are Lead, Mercury, Cadmium and Arsenic. The “action level” (the concentration at which a product would fail) is reported in micrograms per gram (μg/g), which is equivalent to 1000 parts per billion (ppb). Let’s take Mercury as an example. The “action limit” is 0.1 μg/g, which is equal to 100 ppb. Any product testing over allowable levels cannot legally be sold. These metals have already been removed from a variety of household items, such as “lead-free paint,” and mercury-free thermometers.

#6 – Microbials

We’ve all heard or read news stories about lettuce or other agricultural products that get recalled due to e.coli. It’s likely you’ve also heard about salmonella outbreaks. These same microbes can be present in hemp or cannabis. The ingestion or inhalation of these microbial pathogens can cause illness, so any presence of these microbial pathogens in a sample would cause it to automatically fail. On this sample CoA, the product that passed all requirements and the results are listed as “ND,” (not detected).

COA form of product with measured levels of contents#7 – Pesticides

This category actually includes pesticides, herbicides, and fungicides. Each state that has legalized cannabis has set its own pesticide list and action levels. California regulations require testing for 66 pesticides and action levels are quite low in comparison to other states. For example, the pesticide Myclobutanil has an “action level” of 100 ppb in California, 9000 ppb in Nevada, and 200 ppb in Washington. On the example CoA, you’ll note that the product passed for all pesticides. Another pesticide, fipronil, is commonly found in flea collars and carry a warning message to make sure to wash hands well after touching.

#8 – Residual Solvents

This is tested on any product that is not the actual hemp or cannabis flower. Solvents are used to extract the plant oils, which can be made into oils for vaporizor (“vape”) pens and other formats also for inhalation. It can also be infused into other products, such as tinctures, edibles such as candies and chocolates, and even beverages. When the procedure for extraction is not done using best practices, some of the solvent can remain in the product, which could be harmful whether ingested or inhaled. Since there are “allowable” amounts of these, you’ll notice there is a numeric value for Acetone, meaning it was detected in the product. Because the amount in the product is still within the allowable limits, the product still passes.

There’s so much more detail and explanation of the science, however the takeaway message is, much like the food we eat, it’s important to know it’s safe and healthy for consumption. There’s a tremendous amount of information out there for those who are interested in delving deeper. For the average consumer, though, just knowing that products have been tested for purity, safety, and are accurately labeled is a great start.


Written by: Shuli Suman, Owner/Founder - True Science Laboratories 

Written by Svn Space

1 comment

In a certificate of analysis is it also reported the expiry date of the product?

Maria Togrou February 12, 2021

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