Decrease检测模式下新生儿黄疸患者直接胆红素假性增高的原因分析

Analysis of the Cause of False Increase of Direct Bilirubin in Neonatal Jaundice Patients under Decrease Detection Mode

目的通过新生儿黄疸患者Decrease模式下直接胆红素假性增高的病例,探讨Decrease模式在钒酸盐氧化法检测血清直接胆红素中的可行性。方法收集2018年8月—2019年9月确诊为新生儿黄疸高胆红素血症的患者156例,采用原样和不同的稀释倍数分析检测患儿血清标本中的胆红素。结果原样:总胆红素(244.4±38.2)μmol/L、直接胆红素(15.5±4.2)μmol/L、间接胆红素(228.7±37.4)μmol/L;2倍稀释:总胆红素(244.7±38.5)μmol/L、直接胆红素(19.2±5.3)μmol/L、间接胆红素(225.6±36.6)μmol/L;5倍稀释:总胆红素(245.3±39.2)μmol/L、直接胆红素(53.6±10.4)μmol/L、间接胆红素(191.7±32.5)μmol/L;Decrease模式:总胆红素(243.6±37.3)μmol/L、直接胆红素(78.7±18.7)μmol/L、间接胆红素(164.8±26.5)μmol/L。不同稀释倍数与原样比较,总胆红素差异无统计学意义(P>0.05),直接胆红素和间接胆红素在2倍稀释时差异无统计学意义(P>0.05),在5倍和Decrease模式时差异有统计学意义(P<0.05)。结论选择Decrease模式检测非肝胆疾病、非ABO溶血的新生儿黄疸及高胆红素血症的患儿血清标本,随着稀释倍数的增大,大量稀释液改变了待测样本的pH值,导致表面活性剂酒石酸盐不能完全抑制样本中的间接胆红素,使直接胆红素显著假性升高。提示钒酸盐氧化法测定血清直接胆红素对反应的PH值要求严格,高稀释倍数的Decrease模式不适用于新生儿黄疸及高胆红素血症患儿血清直接胆红素水平的检查。Decrease模式设置时应结合仪器的检测限,对不同的生化免疫检测项目设置不同的稀释倍数,在临床检验工作中,当患者测定结果大于仪器的检测限时应尽量选择较低的稀释倍数来稀释样本,防止检验结果假性增高,误导临床的诊断和治疗。

Objective To investigate the feasibility of Decrease mode in the detection of direct bilirubin in serum by the vanadate oxidation method in cases of falsely increased direct bilirubin in neonatal jaundice patients. Methods A total of 156 patients diagnosed with neonatal jaundice and hyperbilirubinemia from August 2018 to September 2019 were collected. The original samples and different dilution factors were used to analyze the bilirubin in the children’s serum samples. Results Original sample: total bilirubin(244.4±38.2)μmol/L, direct bilirubin(15.5±4.2)μmol/L, indirect bilirubin(228.7±37.4)μmol/L;2 times dilution: total bilirubin(244.7±38.5)μmol/L, direct bilirubin(19.2±5.3)μmol/L, indirect bilirubin(225.6±36.6)μmol/L;5-fold dilution: total bilirubin(245.3±39.2)μmol/L, direct bilirubin(53.6±10.4)μmol/L, indirect bilirubin(191.7±32.5)μmol/L;Decrease mode: total Bilirubin(243.6±37.3)μmol/L, direct bilirubin(78.7±18.7)μmol/L, indirect bilirubin(164.8±26.5)μmol/L.Comparing different dilution multiples with the original, total bilirubin, being not statistically significant(P<0.05),direct bilirubin and indirect bilirubin at 2 times dilution, being not statistically significant(P<0.05), at 5 times and Decrease mode,being statistically significant(P<0.05). Conclusion Decrease mode is selected to detect serum samples of children with nonhepatobiliary diseases, non-ABO hemolytic neonatal jaundice and hyperbilirubinemia. As the dilution factor increases, a large number of dilutions change the pH value of the sample to be tested, resulting in surfactant tartrate cannot completely inhibit the indirect bilirubin in the sample, causing a significant false increase in direct bilirubin. It is suggested that the determination of serum direct bilirubin by vanadate oxidation method has strict requirements on the pH value of the reaction,and the Decrease mode of high dilution is not suitable for the examination of serum direct bilirubin levels in children with neonatal jaundice and hyperbilirubinemia. When setting the Decrease mode, you should combine the detection limit of the instrument and set different dilution multiples for different biochemical and immunoassay items. In clinical laboratory work,when the patient’s measurement result is greater than the detection limit of the instrument, try to choose a lower dilution multiple to dilute the sample, to prevent false increase of test results, misleading clinical diagnosis and treatment.