Final answer:
Constancy in a dose calibrator is typically checked daily, while linearity may be checked quarterly or annually. Calibration curves relate known concentrations to response for quantification purposes. New indirect methods of counting live cells include flow cytometry and fluorescence-based viability assays.
Step-by-step explanation:
The frequency of checks on a dose calibrator varies according to the specific protocols of a facility and regulatory guidelines, but generally, constancy should be checked daily to ensure the instrument is working correctly. Linearity, which is the ability of the device to produce outputs proportional to the input doses, is usually checked after any repair, modification, or on a scheduled basis which might be quarterly or annually depending on regulatory requirements.
In a broader context, for intra and interday precision and accuracy assessment in a pharmaceutical setting, a quality control chemist may perform multiple validation runs, typically 3-5, to assess the effects of dilution on precision and accuracy and to ensure extraction recovery assessment for the parent drug, metabolites, and internal standards.
When creating a calibration curve, its purpose is to establish a relationship between known concentrations and the measured instrument response (like turbidity in the case of cell counts). Newer indirect methods of counting live cells might involve techniques like flow cytometry, which can distinguish between live and dead cells, or fluorescence-based methods that differentiate cell viability based on metabolic activity.