Objective To evaluate the role of substrate depletion limit parameters(enzyme linearity extension function) in BS-2000M2 automatic chemistry analysis system.Methods High-level samples were determined parallelly by decreased volume parameters(dilution) and substrate depletion limit parameters(enzyme linearity extension function). A total of 10 common kinetic chemistry items were involved,including alanine aminotransferase (ALT),aspartate aminotransferase(AST),alkaline phosphatase(ALP),gamma-glutamyltransferase (GGT),lactate dehydrogenase(LDH),alpha-hydroxybutyrate dehydrogenase(α-HBDH),creatine kinase (CK),creatine kinase MB isoenzyme(CK-MB),alpha-amylase(α-AMY) and urea. The relative biases between enzyme linearity extension function and dilution were calculated. The main wavelength absorbance(A) at the end point of reaction range was recorded to determine whether substrate depletion occurred. The effectiveness of parameters was evaluated by comparing manual calculation results with actual reaction curve or result flags. Results According to the criteria of WS/T403—2012 or allowable total error(TEa) from the National Center for Clinical Laboratories' external quality assessment,the reportable ranges' upper limits of ALT,AST,ALP,GGT, LDH,α-HBDH,CK,CK-MB,α-AMY and urea were extended to 3339 U/L,7411 U/L,3407 U/L,3945 U/L,7646 U/L,9783 U/L,14106 U/L,3296 U/L,9700 U/L and 54 mmol/L,respectively. The manual calculation results were consistent with actual reaction curve or resultflags,and no false positive or negative substrate depletion was observed. According to the sample level distribution of ALT,AST,ALP,GGT,LDH,α-HBDH,CK,CK-MB,α-AMY and urea,100.00％,100.00％,100.00％,100.00％,100.00％,100.00％,99.96％,100.00％, 100.00％ and 99.97％ of samples can be obtainedfinal results through a single assay,when enzyme linearity extension function was employed. No error result occurred in all samples.Conclusions The enzyme linearity extension function in BS-2000M2 can effectively solve the risk of false negative results for high-level samples,reduce rerun frequency and shorten sample turn-around time.%目的 评价BS-2000M2全自动生化检测系统(简称BS-2000M2)底物耗尽限参数(即酶线性扩展功能)的临床应用效果.方法 采用BS-2000M2减量参数(稀释法)和底物耗尽限参数(酶线性扩展功能)平行测定临床常用的10项动力学法生化检测项目[丙氨酸氨基转移酶(ALT)、天门冬氨酸氨基转移酶(AST)、碱性磷酸酶(ALP)、γ-谷氨酰基转移酶(GGT)、乳酸脱氢酶(LDH)、α-羟基丁酸脱氢酶(α-HBDH)、肌酸激酶(CK)、肌酸激酶MB同工酶(CK-MB)、α-淀粉酶(α-AMY)和尿素]的高浓度样本,计算酶线性扩展功能检测结果相对于稀释法检测结果的偏差.记录反应区间终点的主波长吸光度(A)值,手工计算是否发生底物耗尽,与实际反应曲线或仪器结果标记进行比较,以判断参数设置的有效性.结果 以我国卫生行业标准WS/T 403—2012规定的分析质量目标或国家卫生计生委临床检验中心室间质评允许总误差(TEa)作为可接受标准,ALT、AST、ALP、GGT、LDH、α-HBDH、CK、CK-MB、α-AMY和尿素底物耗尽最大可报告范围上限分别扩展至3339 U/L、7411 U/L、3407 U/L、3945 U/L、7646 U/L、9783 U/L、14106 U/L、3296 U/L、9700 U/L和54 mmol/L.手工计算是否发生底物耗尽与实际反应曲线或仪器结果标记一致,未出现误报或漏报底物耗尽现象.依据临床样本浓度分布,采用酶线性扩展功能后,ALT、AST、ALP、GGT、LDH、α-HBDH、CK、CK-MB、α-AMY和尿素分别可保证100.00％、100.00％、100.00％、100.00％、100.00％、100.00％、99.96％、100.00％、100.00％和99.97％的样本可以一次检测即获得最终结果,且所有样本无错误结果出现.结论 BS-2000M2的酶线性扩展功能可有效解决高浓度样本假阴性结果的风险,降低了重测频率,缩短了样本周转时间.
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