Kristensen Gunn B B, Christensen Nina Gade, Thue Geir, Sandberg Sverre
NOKLUS, Norwegian Quality Improvement of Primary Care Laboratories, Section for General Practice, Department of Public Health and Primary Health Care, University of Bergen, Bergen, Norway.
Clin Chem. 2005 Sep;51(9):1632-6. doi: 10.1373/clinchem.2005.049080.
External quality assessment schemes (EQAS) are conducted to evaluate user performance (participant assessment) and to assess different methods and instruments (method assessment). The quality of control materials is crucial to achieving these goals. Inconsistencies in between-lot variations detected by use of different control and sample materials may affect EQAS outcomes.
For the Accu-Chek Sensor, Precision Xtra, Ascensia Elite, and HemoCue 201 glucometers, 3 different lots of glucose strips were used with each instrument. Method assessment results from analysis of capillary blood and 3 control materials were used to calculate between-lot differences. A simulation study was performed to evaluate the effect of between-lot variation on participant assessment results.
With the Precision Xtra, the results obtained with EQA control material mirrored those obtained with capillary blood, but for the other instruments, we found between-lot differences of as much as 1.3 mmol/L, which were substantially greater than those found with capillary blood and of clinical importance at decision limits. The simulation study showed an effect on participant assessment results related to the target values, with the percentage of poor results decreasing (38%, 10%, and 4%) with the use of common, method-specific, and lot-specific target values, respectively.
Between-lot variation may influence participant EQA results for participant and method assessments. The clinical relevance of between-lot variation discovered in EQAS using noncommutable control materials should be examined by use of native blood samples.
开展外部质量评估计划（EQAS）旨在评估用户表现（参与者评估）以及评估不同方法和仪器（方法评估）。对照材料的质量对于实现这些目标至关重要。使用不同对照和样本材料检测到的批次间差异不一致可能会影响EQAS结果。
对于拜安易血糖仪、稳豪倍易血糖仪、罗氏优越血糖仪和血红蛋白201血糖仪，每种仪器使用3个不同批次的血糖试纸。通过分析毛细血管血和3种对照材料的方法评估结果来计算批次间差异。进行了一项模拟研究以评估批次间差异对参与者评估结果的影响。
使用稳豪倍易血糖仪时，EQA对照材料获得的结果与毛细血管血获得的结果一致，但对于其他仪器，我们发现批次间差异高达1.3 mmol/L，这大大高于毛细血管血的差异，并且在决策限值时具有临床重要性。模拟研究显示了与目标值相关的对参与者评估结果的影响，分别使用通用、方法特定和批次特定目标值时，差结果的百分比降低（38%、10%和4%）。
批次间差异可能会影响参与者EQA结果的参与者和方法评估。在使用不可互换对照材料的EQAS中发现的批次间差异的临床相关性应通过使用天然血样进行检查。
