IQMH is pleased to share this article prepared and authored by: Angela C. Rutledge (lead author), Anna Johnston, Ronald A. Booth, Kika Veljkovic, Dana Bailey, Hilde Vandenberghe, Gayle Waite, Lynn C. Allen, Andrew Don-Wauchope, Pak Cheung Chan, Julia Stemp, Pamela Edmond, Victor Leung, Berna Aslan.
Lot verification practices in Ontario clinical chemistry laboratories — Results of a patterns-of-practice survey.
- Surveyed laboratories verified new reagent lots more commonly than calibrator lots.
- Quality control material was used more than patient material for lot verifications.
- Quality control results with a new lot were compared most to 2 standard deviations.
- Percent difference was used most to assess patient material results between lots.
- Laboratories need feasible guidelines on reagent and calibrator lot verifications.
Objectives: Verifying new reagent or calibrator lots is crucial for maintaining consistent test performance. IQMH conducted a patterns-of-practice survey and follow-up case study to collect information on lot verification practices in Ontario.
Methods: The survey had 17 multiple-choice questions and was distributed to 183 licensed laboratories. Participants provided information on materials used and approval/rejection criteria for their lot verification procedures for eight classes of testing systems. The case study provided a set of lot comparison data and was distributed to 132 laboratories. Responses were reviewed by IQMH scientific committees.
Results: Of the 175 laboratories that responded regarding reagent lot verifications, 74% verified all tests, 11% some, and 15% none. Of the 171 laboratories that responded regarding calibrator lot verifications, 39% verified all calibrators, 4% some, and 57% none. Reasons for not performing verifications ranged from difficulty performing parallel testing to high reagent cost. For automated chemistry assays and immunoassays, 23% of laboratories did not include patient-derived materials in reagent lot verifications and 42% included five to six patient materials; 58% of laboratories did not include patient-derived materials in calibrator lot verifications and 23% included five to six patient materials. Different combinations of test-specific rules were used for acceptance criteria. For a failed lot, 98% of laboratories would investigate further and take corrective actions. Forty-three percent of laboratories would accept the new reagent lot in the case study.
Conclusion: Responses to the survey and case study demonstrated variability in lot verification practices among laboratories.
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