Laboratory documentation guide

How to read a certificate of analysis

A certificate is useful only when the document can be connected to the exact material being reviewed.

Start with the match

Confirm the product name, batch or lot identifier, sample identifier, and report number. A result from a different lot is not evidence for the material in hand.

Read the method and result together

Record which analytical method was used, the reported value, units, specification or acceptance criterion, and any uncertainty or limitation stated by the laboratory. NIST describes certified reference documents as including intended use and characterized values; the same discipline helps when evaluating commercial records.

Check document integrity

• Laboratory identity and contact information
• Issue and test dates
• Authorized signature or verifiable report status
• Sample and batch identifiers
• Method, result, units, and stated limits
• Version, amendment, or expiration information

Do not overread one result

A purity result does not automatically establish identity, sterility, endotoxin status, concentration, or fitness for a particular use. Each claim requires evidence suited to that question.