Silva Dalsasso Joaquim Lisiê, Granzotto Natalli, Dos Santos Laís Fernanda, Fontana Roman Camila, Martinello Flávia
Department of Clinical Analysis, Federal University of Santa Catarina, Florianópolis, Brazil.
J Clin Lab Anal. 2019 Mar;33(3):e22823. doi: 10.1002/jcla.22823. Epub 2018 Nov 29.
The adenosine deaminase (ADA) enzyme is a marker of inflammatory processes whose activity can be measured through a colorimetric method developed as an in-house assay. This validation can reduce costs and expand the alternatives for laboratory diagnosis.
The ADA analysis was achieved through a modified form of Giusti and Galanti's (1984) method. The following parameters were characterized: calibration curve, linearity, analytical sensitivity, limit of detection, limit of quantification, method working range, precision (within-assay and between-assay), bias, total analytical error, and sample stability. The results were statistically evaluated and compared with quality specifications based on biological variations and the performance of commercial tests.
The analytical sensitivity and limit of detection (0.013 and 3.0 U/L, respectively) were lower than those of commercial tests. The method's working range was 3.2-100.0 U/L. According to the quality specification, the method showed optimum performance with a bias <3.5%. However, repeatability (2.2% and 1.7% for normal- and high-activity samples, respectively) and reproducibility achieved worse results when compared to commercial tests. The method demonstrated an inappropriate between-assay precision for low enzymatic activity (10.4%) and the minimum and desirable performance for medium (8.8%) and high (5.0%) activities, respectively. It also presented at least a minimum performance (<25%) for the total analytical error of the three analyzed samples. The pleural fluid samples were found to be stable at -20°C for six days.
The findings show that the in-house method displays an acceptable performance and is capable of generating results comparable to existing commercial tests.
腺苷脱氨酶（ADA）是炎症过程的一个标志物，其活性可通过一种作为内部检测方法开发的比色法进行测定。这种验证可以降低成本，并扩大实验室诊断的选择。
通过对朱斯蒂和加兰蒂（1984年）方法的改良形式进行ADA分析。对以下参数进行了表征：校准曲线、线性、分析灵敏度、检测限、定量限、方法工作范围、精密度（批内和批间）、偏差、总分析误差和样品稳定性。对结果进行了统计评估，并与基于生物学变异和商业检测性能的质量规范进行了比较。
分析灵敏度和检测限（分别为0.013和3.0 U/L）低于商业检测。该方法的工作范围为3.2 - 100.0 U/L。根据质量规范，该方法在偏差<3.5%时表现出最佳性能。然而，与商业检测相比，重复性（正常和高活性样品分别为2.2%和1.7%）和再现性结果较差。该方法对低酶活性（10.4%）的批间精密度不合适，对中等（8.8%）和高（5.0%）活性分别表现出最低和理想的性能。对于三个分析样品的总分析误差，它也至少表现出最低性能（<25%）。发现胸腔积液样品在-20°C下可稳定保存六天。
研究结果表明，内部方法表现出可接受的性能，能够产生与现有商业检测相当的结果。
