How to Read a Certificate of Analysis (COA) for Heavy Metals

A Certificate of Analysis (COA) is one of the most important documents in product transparency. It provides laboratory results showing the concentration of specific substances—such as lead, arsenic, cadmium, and mercury—found in a tested batch.

But not all COAs are equally informative.

When reviewing a COA for heavy metals, there are several key elements to look for:

1. The Testing Method
Was the analysis performed using a validated method such as ICP-MS? The method matters because detection limits and accuracy depend on the instrumentation used.

2. Units of Measurement
Are results reported in parts per billion (ppb), micrograms per gram (µg/g), or micrograms per daily serving (µg/day)? Understanding the unit is critical when comparing results to regulatory benchmarks like Prop 65 or USP limits.

3. Batch Identification
Does the COA clearly identify the batch or lot number tested? Transparency requires traceability.

4. Detection Limits
Are “non-detect” values accompanied by a stated detection limit? Without that number, “non-detect” lacks context.

5. Date and Laboratory Information
Is the testing laboratory identified, and is the report dated? Independent third-party verification strengthens credibility.

A COA should provide clarity—not just reassurance. The goal of transparency is not to overwhelm consumers with technical detail, but to ensure that claims are supported by measurable, documented evidence.

At hMAP, we believe accessible reporting standards are essential to improving trust between brands and the public.