Defining good User Requirement Specifications (URS) is of the utmost importance in the Analytical Instrument Qualification (AIQ) process. Creating a well-defined URS will ensure an efficient and qualitative AIQ process that will result in an instrument that is compliant with the requirements set by regulating bodies such as FDA or FAGG.
Let’s start with the why
USP <1058> defines Analytical Instrument Qualification as the collection of documented evidence that an instrument performs suitably for its intended purpose. Using qualified instruments in analyses is necessary to be able to generate valid data. In other words, acquiring accurate, precise and reliable data from analysis is only possible when it is performed with qualified instruments.
User Requirement Specification
In Analytical Instrument Qualification the qualities an analytical instrument must possess are translated into User Requirement Specifications and they form the cornerstone of the equipment qualification process. A User Requirement Specification describes the quality an analytical instrument or its associated software must possess. For analytical instruments they can be based on ALCOA principles, FDA Part 11 requirements (computerized systems) and other instrument specific regulatory requirements.
Like any other project it is important to have a thorough understanding of what the project originator needs and expects at the end of the project. So, when drawing up a URS, it is important to define all the quality specifications an analytical instrument must comply with.
By writing well thought through and well-defined user requirements, the equipment qualification can be performed more efficiently. After all it is based on these URSs that all other qualification documentation, such as test scripts, will be compiled and the actual qualification is performed. These URSs can be compiled into several documents depending on the testing phase they are attributed to. The combination of these documents outlines all the requirements a new - still to be purchased - analytical instrument must be able to fulfill. When drafting these documents, it is advisable to get feedback from the end users of the system, the quality department and if available one or more subject matter experts who are familiar with the equipment qualification process and/or who have experience with similar analytical instruments. After approval of the URSs the requirements are sent to the equipment manufacturer to verify if they can meet the requirements set out in the documents.
Qualities of well-defined User Requirement Specifications
1. Clear & Objective
Make sure that your user requirements specifications are not open for interpretation. Having clear and objective URS makes it easier to write test steps to test the URSs during the qualification phase. It will also provoke less discussion if you would ever need to defend the documented test evidence for a certain URS during a potential audit.
2. Measurable / Testable
The URS should always be measurable or testable. Which means that you should be able to design tests for you URS. If no documentation can be created that supports the claim of the URS than you should rethink and redefine the URS. For example, the following URSs are not measurable and should be avoided “The system should never breakdown” or “The instrument should be 100% reliable”.
3. Realistic / Achievable
In general, you should not set requirements which are stricter than the specifications of the manufacturer. Even the specifications set by the instrument manufacturer should not always be literally translated to a URS. Keep in mind that these specifications were achieved in a meticulously controlled environment by instrument experts. The laboratory environment in which the instrument will eventually end up, might not be so well controlled, exposing the instrument to conditions under which it cannot achieve the specifications set out by the supplier.
With the term consistent we refer to two features of the URS document. Firstly, the requirements should not contradict and should thus be in line with each other. Secondly you should remain concise in the phrasing used to describe a certain part or quality of the instrument.
Pitfalls when writing a URS document
• Not involving the equipment manufacturer when purchasing off the shelf equipment
• Setting user requirements which are impossible to achieve
• Combining multiple requirements into one single URS
• Unclear and subjective user requirement specifications
• Incorporating additional functions in the URS document which will not be used during routine use of the instrument. These additional functions can make the qualification process unnecessary complex and might cause failures which could have been avoided by not including them in the scope of the qualification project.
The benefits of well-defined User Requirements Specifications
• Time and cost-efficient qualification process
• The end product is what the end user expects
• Qualified Analytical Instruments which comply with regulatory requirements
• No rework during the qualification phase
• Reliable analysis data
Since the URS document will be the basis from which all other qualification documentation will be drafted it is essential that enough time is spent developing the URS document and to involve all possible stakeholders in this process. User Requirement Specifications with the right characteristics can aid tremendously during the qualification process.
Laurens Van Hove
QC consultant @ pi