Objective: The opportunity to apply a sampling plan was evaluated. Costs were computed by a microcosting study.
Setting: In 2003, a sampling plan was defined to reduce the number of chemotherapy quality controls while preserving the same level of quality. Recent qualitative and quantitative changes led us to define a second sampling plan supplemented by an economic evaluation to determine the cost and cost-savings of quality control.
Methods: The study considers preparation produced during four semesters classified into three groups. The first one includes drugs produced below 200 batches a semester. Group 2, those for which the lot of preparation lots would have been rejected twice among these four semesters. Group 3, those would have been accepted (≥3 'acceptable lot'). A single sampling plan by attributes was applied to this group with an acceptance quality level of 1.65% and a lot tolerance percent defective below 5%. A micro-costing study was conducted on quality control, from the sampling to the validation of the results.
Results: Among 39 cytotoxic drugs, 11 were sampled which enabled to avoid a mean of 17,512 control assays per year. Each batch of the 28 non-sampled drugs was however analyzed. Costs were estimated at 2.98€ and 5.25€ for control assays depending of the analytical method. The savings from the application of the sampling plans was 153,207€ in 6 years.
Conclusion: The sampling plan allowed maintaining constancy in number of controls and the level of quality with significant costsavings, despite a substantial increase in drugs to assay and in the number of preparations produced.