How do you read a certificate of analysis (COA)?
Read a certificate of analysis top to bottom in this order: who tested it, which sample and lot it describes, when, which methods were run, what the results were, and how to verify it on the lab's own site.
How do you do it, step by step?
- Identify the lab. Find the lab's name, address and report or certificate number. You will need the number to look the report up on the lab's own site.
- Identify the client. The client is whoever paid for the test. It may be a manufacturer rather than the seller, which should be explained.
- Match the sample and lot ID. Find the sample description and the lot or batch ID. The lot ID must match the one printed on your vial label.
- Check the dates. Look at the sample received date and the report date. A report much older than the lot you hold, or dated before the lot existed, does not describe it.
- Read the methods. Each result should name the method used, such as HPLC or mass spectrometry. A result with no method is hard to evaluate.
- Read the results and limits. Each result should show a value, a unit and, where relevant, a specification or limit. "Not tested" is not the same as "passed".
- Find the verification code. Look for a report number, task number and key, or QR code that lets you open the lab's own copy. Then compare it with the copy you were given.
What does a COA prove?
Only what the lab measured, for the sample it received. It ties to your vial only if the lot ID matches and the lab's own record confirms the report.
What if a test isn't on the COA?
Then it wasn't reported. A COA can only show what was measured; a missing test is neither a pass nor a fail.
What is the difference between a COA and a lab-side record?
A COA is the document you are shown. A lab-side record is the lab's own copy on its own website, which you can use to check the document hasn't been edited.