THE PURPOSE
Of the study is to assess the quality of immunochemical studies using sigma-metrics and selecting requirements for analytical quality based on its current state-of-the-art.
MATERIALS AND METHODS
The retrospective analysis of intra-laboratory quality control data was conducted for the period from August 2023 to March 2024, for 19 immunochemical indicators (TSH, LH, FSH, estradiol, testosterone, prolactin, progesterone, cortisol, C-peptide, insulin, total PSA, CA-125, CA 15-3, CA 19-9, CEA, AFP, ferritin, vitamin B9, vitamin B12). The studies were carried out using closed automated immunochemical analyzers UniCel DxI800 (Beckman Coulter, USA) and Cobas e411 (Roche Diagnostics International Ltd., Germany). To establish analytical quality requirements in the TEa format, consolidated data for immunochemical studies published on the website Dr. James O. Westgard was utilized. For intra-laboratory quality control, certified control materials from an independent manufacturer — Lyphochek Immunoassay Plus Control and Lyphochek Tumor Marker Plus Control (Bio-Rad, USA) were used. Sigma calculation was performed automatically in the interlaboratory comparison program Unity Real Time («Bio-Rad Laboratories», USA).
RESULTS
In the first stage of sigma-metrics analysis, when setting the requirements for analytical quality at the level of recommended values, 3 analytes demonstrated excellent results with a Sigma level ≥6. However, 8 analytes showed unsatisfactory results with a Sigma level ≤3.5. After adjusting the quality requirements, 3 analytes still could not exceed the 3.5. Depending on the Sigma level, laboratory parameters were divided into 3 groups: Sigma ≥6 — testosterone (level 2), C-peptide, insulin; Sigma from 3.5 to 6 — TSH, cortisol, testosterone (level 1), estradiol, prolactin, PSA, CA 125, CA 15-3, CA 19-9, CEA, AFP; ferritin, vitamin B9, vitamin B12; Sigma ≤3.5 — LH, FSH, progesterone.
CONCLUSION
The assessment of the quality of immunochemical studies using sigma-metrics and the selection of analytical quality requirements based on its current state (state-of-the-art) allowed for a quantitative evaluation of the achieved quality level. It concluded that, overall, both analytical systems are under control. However, there are analytes that require special attention and actions to improve the analytical process.
