In this article3 min
A certificate of analysis, or COA, is the lab report behind a production lot. It lists each test that was run, the limit the product had to meet and the result. If your name is on the label, it is the document that backs the product up.
Most COAs follow the same order from top to bottom. Here is what to look for in each part.
1. Who ran the test
The top of the report should name the testing laboratory and its accreditation. Look for a lab that is independent of the company selling the product. A report printed on the supplier’s own letterhead is not an independent test.
2. Report number, lot number and dates
Every report should carry its own report number, the lot number it covers and the dates the sample was received and tested. The lot on the report should match the lot printed on the vial in your hand. One report reused for every batch tells you nothing about the batch you received.
3. What was tested
This section names the compound, its form (for example, lyophilized powder), the amount stated per vial and how many vials went to the lab. Testing more than one vial shows whether the lot is consistent from vial to vial.
4. Identity
Identity testing confirms the vial holds the compound named on the label, checked against a certified reference standard. Purity alone cannot do this: a very pure sample of the wrong compound still scores high on purity.
5. Purity and the chart behind it
Purity is the share of the sample that is the target compound, usually measured by HPLC. A good report shows the method, the specification the result had to meet and the chromatogram, the chart the number comes from. A purity figure with no method and no chart cannot be checked.
6. The contaminant panel
Purity tells you what is in the vial. The contaminant panel tells you what is not: bacterial endotoxins, sterility, heavy metals, residual solvents, microbial limits and contaminant screens. When a result reads “< LOD”, it means below what the instrument can detect.
7. Limits, verdict and sign-off
Each result should sit next to the limit it had to meet, followed by an overall verdict and the signature and date of the lab’s approving reviewer.
A signed pass against a stated limit is a record you can stand behind if a client or partner asks.
When to ask questions
- No lab is named, or the report is on the supplier’s letterhead
- The lot number is missing or does not match your product
- There is a purity result but no identity test
- Results are listed without limits, method or chart
- There is no signature or date, or the page looks edited
Every lot we supply comes with its own report. If you are a registered partner, your dedicated contact can send the COA for any lot you receive. You can also see a fully annotated specimen report on our COA and purity page.
