“Not tested”: endotoxin, sterility and what a missing test means

A COA often reports identity, purity and quantity, then lists other tests as “not tested” or leaves them out entirely. That gap matters when you read the report, because the absence of a test result is information too — just not the information many people assume.

What the common extra tests measure

• Bacterial endotoxin — detects endotoxin from certain bacteria in the sample, reported in endotoxin units (EU), often per vial.
• Sterility — checks whether viable microorganisms grow from the sample. Reports sometimes state counts such as TAMC and TYMC (total aerobic microbial count and total yeast and mould count).
• Heavy metals — measures trace metals such as arsenic, cadmium, lead and mercury.
• Residual solvents and counter-ions — measures leftovers from manufacture and the salts the peptide is supplied with, such as trifluoroacetic acid (TFA).

Reading an incomplete report

• List what was tested and what wasn’t. The second list is part of the report.
• Don’t carry a result from one property to another. A good purity result says nothing about sterility.
• A result applies to the tested sample. A report for one batch doesn’t cover another batch or a later one.
• If a test is shown, check it names a method and a unit, and ask whether it covers the vial or a separate sample.

How PeptideProof treats these rows

When a report says a test was “not tested”, “not performed” or similar, PeptideProof lists it as no evidence located. It does not count it toward the evidence score, and it never turns a missing test into a favourable result. You can see this in the example report, where endotoxin and sterility are marked “Not tested”.

For the full picture, see how to read a peptide COA.