DS / DDS
Design Specification / Detailed Design Specification
What a definition is not
A definition is SPEQ’s plain-language decode of how a term is used in practice, cited to the documents that define it. It is a practitioner reference, not legal or regulatory advice, it does not replace the definition in the source, and where a regulator’s wording differs the regulator’s wording governs.
The document that states how a system will be built to deliver the specified functions — components, materials, instrument ranges, software architecture, network topology. Where the functional specification says what, the design specification says with what.
The design specification states how a system will be built to deliver the specified functions: components, materials, instrument ranges, software architecture, and the physical and logical arrangement. It is the document installation verification is performed against, which is why vagueness here is expensive later — an IQ can only confirm that what was installed matches what was specified if the specification said something specific.
Materials and ranges are the fields that most often cause trouble. A product-contact material specified by family rather than by grade, or an instrument range chosen for convenience rather than for the operating point, passes review and fails in use: the first at cleaning validation or extractables assessment, the second as an instrument operating at the bottom of its span where its accuracy is worst.
It should also record what was deliberately not specified and left to the supplier, because an unstated delegation looks identical to an omission when someone reviews the package two years later.
- —The document installation verification is performed against.
- —Vague specification makes IQ unable to confirm anything specific.
- —Product-contact materials specified by family rather than grade cause problems downstream.
- —Instrument ranges chosen for convenience put the operating point where accuracy is worst.
- —Record what was deliberately delegated to the supplier — otherwise it reads as an omission.
ISPE GAMP 5 (2nd ed., 2022) specification hierarchy; EU GMP Annex 11 §4.
Frequently asked questions
What does DS / DDS stand for?
DS / DDS stands for Design Specification / Detailed Design Specification.
What is DS / DDS?
The document that states how a system will be built to deliver the specified functions — components, materials, instrument ranges, software architecture, network topology. Where the functional specification says what, the design specification says with what.
Which regulations cover DS / DDS?
ISPE GAMP 5 (2nd ed., 2022) specification hierarchy; EU GMP Annex 11 §4.