Biomedical Engineering Reference
In-Depth Information
quantitative term describing the difference between the
average of measurements made on the same object and
its true value.”
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Calibration weights are classifi ed in accordance with the
recommendations of the International Organization of Legal
Metrology.
23
Classes of weights include E1, E2, F1, F2, M1,
M2, and M3, ranging from the highest accuracy weights (E1;
maximum error at 1 kg is ±0.5 mg) to the lowest (M3;
maximum error at 1 kg is ±500 mg). The higher-class weights
are far more expensive than the lower-class weights. Each
weight class is “traceable” - tested against a standard of
higher accuracy (i.e., the next higher weight class).
24
Speaking in general of a written procedure for the
calibration of equipment, FDA has suggested
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that the SOP
include the sections listed in Table 3.5.
From a compliance standpoint, the eight topics listed in
Table 3.5 are important. FDA has made inspectional
observations on organizations that have not adequately
addressed these topics. As an example of the failure to
address the frequency of calibration, and its GXP implications,
see the FDA Warning Letter to International Biologicals
Table 3.5
Outline of SOP for the calibration of equipment
1. Purpose and scope
2. Frequency of calibration
3. Equipment and standards required
4. Limits for accuracy and precision
5. Preliminary examinations and operations
6. Calibration process description
7. Remedial action for product
8. Documentation requirements
