internal quality control 

Initialism: IQC
https://doi.org/10.1351/goldbook.08082
Quality control within a specified laboratory.
Source:
PAC, 2021, 93, 997. 'Metrological and quality concepts in analytical chemistry (IUPAC Recommendations 2021)' on page 1029 (https://doi.org/10.1515/pac-2019-0819)