A guide to research terminology

Batch, lot and traceability

A batch or lot is an identified quantity produced or handled under defined conditions. The identifier connects a product to records such as receipt information, testing documentation and inventory movements. Traceability is the ability to follow that connection through the available records.

Identity, assay and purity

Identity indicates whether analytical evidence is consistent with the stated material. Assay estimates the quantity or concentration of a target under a specified method. Purity describes the relative proportion of the target compared with detected components under that method.

These values answer different questions. Always read the method, units and reporting notes alongside the result.

Specification and acceptance criteria

A specification defines the requirements used to assess a material. Acceptance criteria are the numerical limits, ranges or other conditions a result must meet. A reported result should be compared with the stated criterion rather than viewed in isolation.

LOD, LOQ and uncertainty

The limit of detection (LOD) is the lowest level at which an analytical signal can be distinguished from background under stated conditions. The limit of quantitation (LOQ) is the lowest level that can be measured with suitable performance under the method.

Measurement uncertainty describes doubt associated with a measured result. Its interpretation depends on the method and reporting framework.

Peptide and lyophilised material

A peptide is a compound made from amino acids linked in a chain. Lyophilised material has undergone freeze-drying to remove water under controlled conditions. Neither term indicates approval, intended use, purity or suitability on its own.

Reconstitution means adding a compatible liquid to a dried material under an approved protocol. It changes handling and stability considerations and should only be undertaken in a suitable laboratory setting.