Do tightly grouped results prove measurement accuracy?
No. Results can be consistently biased. Evaluate agreement with an appropriate reference separately from the variation observed in the chosen repeat study.
Repeated scans of material already circulating in one instrument examine a narrower source of variation than separately prepared portions or comparisons between laboratories. State what was repeated and what changed. Reference checks and preparation studies answer different questions and should remain distinguishable in the record.
How can a lab separate preparation variation from instrument variation?
Measure one circulating dispersion repeatedly, then measure independently divided and prepared portions of the same bulk material. Compare the spread within one preparation with the spread between preparations. The second comparison includes sampling and dispersion effects.
Method details to record
| Consideration | What to record |
|---|---|
| Reference basis | Appropriate comparison material |
| Repeat design | Scans, preparations or laboratories |
| Result assessment | Agreement and variation |
Where does a reference check fit?
Measure a suitable reference under its specified conditions and compare the result with its assigned value and acceptance rule. Keep that agreement check separate from the spread among independently prepared production samples.
Explore particle characterization equipment
Review the equipment details and discuss the supported configuration for your sample.