The United States Pharmacopeia (USP) is the American counterpart to the German pharmacopeia and is used by many companies in Germany as a guideline.
The requirements of the USP of balances are recorded in two chapters:
- Chapter 41 is binding and includes requirements on:
- Repeatability / standard deviation of 10 measurements (0.1% with a safety factor of 2)
- Accuracy / sensitivity (0.1% of a test weight> 5% max)
- Chapter 1251 is not binding and contains recommendations to the installation site also proposals for the regular (for example annual) testing of balances in a "Performance Qualification" (PQ). This includes more tests and acceptance criteria for:
- Eccentric load
Compared to the minimum weight as an annex to the DAkkS calibration, the minimum weight is only repeatability considered according to USP. In a DAkkS calibration certificate parameters such as eccentric load or linearity flow into the measurement uncertainty in use. However, they have only a slight impact with small weights.