Sterility: is the sample free from growth?
Testing is performed under controlled conditions while monitoring for bacterial and fungal growth. The result applies to the tested sample and procedure.
Endotoxins: invisible bacterial remains
Endotoxins can remain even when bacteria are no longer alive. Separate methods such as LAL or recombinant assays are used to detect them.
Why does HPLC not show this?
HPLC is designed to separate and quantify chemical compounds. Microorganisms and endotoxins require different sensitivity ranges and procedures.
Transport and packaging matter too
Closure integrity, storage conditions and the supply chain affect a sample after it leaves the laboratory. A report does not describe the product’s entire later history.