Do You Really Have to Validate a Balance?

There is a discussion that seems to come up time and time again at various facilities. Somebody buys a balance sets it up, and is ready to go, and QA comes in and there’s a conversation that goes something like this:

QA: What’s this?
Balance Owner: Our new balance, we just had it calibrated and we’re ready to go.
QA: Hmm, is this for GMP use?
Balance Owner: Yes, its a replacement for the other one that got damaged. Same model and all that.
QA: Ok, well, don’t forget to do the assessment and the validation work before using it for GMP work.
Balance Owner: That’s a good one! Its just a balance, and its calibrated, so we should be good to go with our weight checks.

And the discussion deteriorates from there until everybody understands each other and things are amicably resolved. (Spoiler alert: QA usually wins).

A similar discussion is common regarding movement of balances from one location to another. Should there be a change control?

I am very sympathetic to the arguments of the balance owner, but I think that ultimately, the QA position is often correct. In the first place, virtually any item that could be used for GMP support should be, at the very least, assessed and assigned an ID number.  This ID number then starts a file that contains that assessment and provides traceability to any future work. Of course, this would also be used in the GMP CMMS system (which may include Calibration Management, Maintenance Management, and/or Validation Management). In some cases, GMP CMMS software includes a simple form for this assessment.

If the assessment determines that calibration, validation, or maintenance are not required, then that’s great, and the rationale is documented in the file and software, in case the question comes up in the future.  This is typical for some non-GMP related equipment. This doesn’t prevent the user from performing validation and maintenance, but does allow significantly more flexibility.

If the assessment determines that calibration, validation, or maintenance are required then there are further steps. Since the subject of this article is “validation” of balances, let’s assume that the calibration and maintenance are handled separately and consider why a calibration would not be sufficient and why a validation (and change control) may be required.

There are many issues with regard to the balance operation that are addressed by periodic calibration weight checks. However, there are several that may not be. A brief validation protocol can address some of the following issues not included in a typical calibration (keeping in mind that there is a wide range of tasks that may be included in a calibration, depending on who is performing it, and that some are more comprehensive than others).

Some of the issues that may apply but may not be addressed by a calibration and likely would require some validation work include:

  • Installation environment (temperature and relative humidity which may not be captured by calibration)
  • Surface on which the balance is used (vibration, stiffness, levelness, other activities performed on surface, etc.)
  • Communications with other systems (printers/computers)
  • Configuration of balance (if configurable)
  • Special functionality (e.g. counting) that might be specific to the intended use
  • Any other special requirements that might be unique to the installation
  • Operational procedure verification
  • Security configuration

Most balances these days have self check systems of various levels of sophistication that provide some degree of confidence that the system is operating correctly. Weight checking does significantly reduce the opportunity for problems to remain undetected.

During the initial assessment, each balance can be evaluated to determine if a validation is required to provide a high degree of confidence that the system is installed and operates correctly and in a manner consistent with its intended use. If not, then it is appropriate to do further validation work and change controls as determined by the assessment.  Then all this work can be tracked in your GMP and 21CFR11 compliant calibration, validation, and/or maintenance management program and life is good!