How Kratom Quality Is Measured

A lab report is the one document in this industry that can check a seller’s word, and it checks less than most people think. It can catch a problem in a batch. It can’t tell you the leaf is good, and it can’t stop the next batch from turning out different.

The first level showed you that alkaloid content moves from tree to tree and batch to batch, and had you copy the lab numbers printed on a package. This level turns from you to the industry around the product: how it is tested, studied, regulated and sold¹. This lesson opens the full report behind those numbers. It also covers what a gamma pass is, why the order of testing matters, and what no report can prevent.

What Is a Certificate of Analysis?

It’s a lab’s written result for one sample of material, tested on one day.

A certificate of analysis², or COA, carries a batch number, the date the sample arrived and the date the results went out, the methods the lab used, and each finding set against a limit. Somebody paid for it, usually the seller or the seller’s supplier. That name appears on the report as the client. Know whose test you’re reading.

A COA is a receipt for a test. It isn’t a grade or a seal. It says nothing about your package until you tie the two together.

What Does a Lab Test For?

Three things, in three panels.

The alkaloid panel usually reports mitragynine and 7-hydroxymitragynine, sometimes a few more, out of the dozens the leaf carries. The heavy metals panel looks for lead, arsenic, cadmium and mercury. The microbial panel counts bacteria, yeast and mold, and checks for E. coli and Salmonella, two bacteria that should come back not detected rather than merely low.

A report with only alkaloid figures has answered one question of three.

Metals and Microbes Are on the Panel for a Reason

Both have turned up in kratom sold in the United States.

In 2019 the FDA tested 30 kratom products and found lead and nickel at levels it said exceeded safe daily intake by mouth. That was a calculation built on how much heavy kratom takers reported consuming. The agency wrote that long-term exposure at that rate could harm the nervous system and kidneys. It did not report anyone harmed. A tree takes up what is in its soil, so where the soil carries metals, the leaf can too.

The record on microbes is firmer, because dried leaf is a raw farm product and nothing cooks it between the tree and your kitchen. From January 2017 to May 2018, the CDC counted 199 people in 41 states with Salmonella infections. The evidence pointed to kratom as the likely source. Of the 132 whose records showed it, 50 were hospitalized. Nobody died, and investigators never found one common source. In April 2018 the FDA ordered one company’s powdered kratom recalled after the company refused to recall it voluntarily. It was the first time the agency had ordered a recall of contaminated food.

It didn’t end there. Researchers at a university in Prague tested 96 kratom products sold in the Czech Republic from 2022 to 2024 and found Salmonella in 16, about one in six, at close to the same rate each year. Those products were sold there as not for human consumption, and nobody could verify their origin. The figure describes that market, not ours. The study had no outside grant, and its authors declared no competing interests.

How Do You Read One?

Tie it to your package first, then work down the page.

A report means something only when three things line up: a number printed on your package, a report carrying the same number, and a way to reach that report without asking anyone. Break any of the three and what’s left is a picture of a document. A lot number and a batch number mean the same thing.

Then check the dates: when the sample arrived, when testing finished and when the report was issued. Check the lab, and look for accreditation to ISO/IEC 17025, an international standard for testing labs. It means an outside body has checked the lab’s methods, not just that the lab exists.

Check the units. A lab’s serving and a package’s serving can be different amounts, so read what each column counts before you compare it with anything. In the contaminant results you want every line within its limit, and Not Detected for E. coli and Salmonella. Last, make sure you have the whole report, because a cropped screenshot hides the rest.

You can also call the lab with the report number and ask whether it matches their records. A seller who objects to you checking has told you something.

Why Do Two Labs Return Different Numbers?

Because nobody has set a standard method for testing kratom.

Each lab chooses its own extraction, machine calibration and reference sample. Small differences in any of them move the result. We tested it ourselves. We sent 250 grams of the same powder to each of four labs, and three different numbers came back. None of them was wrong.

So read an alkaloid figure as a reading, not a fact. One lab’s reports compared over time hold up well. One seller’s figure set against another’s, from two different labs, tells you very little.

What Is a Gamma Pass, and Why Does the Order Matter?

A gamma pass runs dried leaf past a source of gamma rays to kill bacteria and mold before it ships.

The FDA allows the same process for dried culinary herbs and spices, up to 30 kilograys. A kilogray is a unit that measures how much radiation the material absorbs. Our own leaf gets a gamma pass³ at 6 kilograys, at a commercial facility near Jakarta, before it leaves Indonesia.

What matters most is when the microbial sample is drawn. Ours is taken after the gamma pass, not before. A result from before describes material that no longer exists by the time anyone reads the report. So when a seller says its kratom was irradiated, ask whether the microbial test came after.

In the Prague study, sellers of some Salmonella-positive samples claimed to sterilize with gamma or ultraviolet light, and nothing in that market let anyone confirm it had happened.

No published study has measured what a gamma pass does to kratom’s alkaloids. That’s an open question, and we’d rather say so than round it off.

Batch Variation Is a Supplier Problem

Alkaloid content moves with light, leaf age, season and drying, as the first lesson of this course showed. That is a fact about the plant. For a seller, it becomes a sourcing job.

A seller buying dried powder is buying something already made at origin. What differs between sellers is how far the figures move, and whether anyone upstream holds them inside a range.

Normal variation⁴ is a figure moving inside a band you can name. Mitragynine on our own leaf’s certificates has run between 1.4 and 1.6 percent since the end of 2021, and it steps outside that only rarely. No two deliveries have read the same. A band like that comes from years of reports out of one source. It took us about eighteen months and about six suppliers to find a source that could hold one.

One batch landing differently is ordinary. A run of batches that changes and stays changed means something upstream has moved.

The word batch is looser than it looks. Farms harvest, dry and mill without stopping, so nobody upstream draws a line around a lot. We define a batch by delivery, because the ocean crossing is where the risk sits, and we test every delivery⁵ before any of it goes on sale. Another seller’s batch number carries that seller’s definition.

What Can’t a Lab Report Prevent?

An inconsistent batch. A report describes a batch that already exists.

Through those eighteen months, the complaints reaching us were about consistency, and the reports behind those deliveries were clean. Nothing on a certificate grades leaf maturity, drying or milling, or tells you this batch will match the last one you liked. One early delivery arrived coarse, lumpy and stale, and we threw it all out before any of it reached a customer.

Testing catches a problem. Sourcing prevents one. A seller showing you only the testing half is showing you the half that’s easier to buy.

What a report does well is rule things out: metals over a limit, bacteria that shouldn’t be there, an alkaloid figure far from what the product usually reads. That’s a good filter. It isn’t a verdict, and the rest you learn by ordering once and watching.

Key Takeaways

• A lab report counts only when its batch number matches your package and you can reach it without asking.
• A full report has three panels: alkaloids, heavy metals and microbes. Both metals and Salmonella have turned up in kratom, which is why the last two panels exist.
• Two labs can return different alkaloid figures for the same powder, so compare one lab’s reports over time, not two sellers’ numbers.
• A claim that kratom was irradiated tells you little unless the microbial test came after the gamma pass.
• A clean report can’t prevent an inconsistent batch. Ask a seller for its range, and watch whether a change holds across deliveries.