血红蛋白、胆红素、乳糜对干化学法和酶速率法检测血氨的干扰研究

Interference effects of hemoglobin,bilirubin and chyle on the measurement of plasma ammonia by dry chemistry method and enzymatic assay method

目的探讨内源性干扰物质血红蛋白(Hb)、胆红素(Bil)和乳糜微粒对酶速率法[谷氨酸脱氢酶(GLDH)法]和干化学法检测血氨的影响。方法根据美国临床实验室标准化协会(CLSI)EP7-A2文件要求收集临床血浆样本,制备高、低2个浓度的基础样本,并配制含不同浓度干扰物(Hb、Bil及乳糜)的干扰血浆样本。分别采用GLDH法和干化学法进行检测,计算干扰样本与基础样本血氨检测结果的相对偏移(高值样本)和绝对偏移(低值样本)。以澳大利亚皇家病理学院(RCPA)的允许偏移标准(血氨≤30μmol/L时为±3μmol/L;血氨>30μmol/L时为±10%)作为临床可接受标准。结果不同浓度的Hb对干化学法检测血氨高、低值样本均无干扰,所有偏移均在允许偏移范围内。Hb对GLDH法检测血氨高、低值样本产生负干扰,且干扰程度随Hb浓度的升高而逐渐增大。Bil对干化学法检测血氨低值样本产生正干扰,当Bil≥184.4μmol/L时已超出允许偏移范围;对高值样本无干扰。不同浓度的Bil对GLDH法检测血氨低值样本均产生负干扰,对于血氨高值样本,当Bil≥246.2μmol/L时,对GLDH法检测产生负干扰。乳糜对干化学法检测血氨高值样本无干扰;浓度为612 FTU时对血氨低值样本产生正干扰,1534 FTU时为负干扰。不同浓度乳糜对GLDH法检测血氨低值样本均产生负干扰,对于血氨高值样本,除乳糜浓度为306 FTU时无干扰外,其他乳糜浓度均产生负干扰。结论干化学法对Hb、Bil及乳糜微粒的抗干扰能力优于GLDH法,但这些干扰物质均会影响2种方法检测血氨的重复性。

Objective To study the interference effects of endogenous substances[hemoglobin(Hb),bilirubin(Bil)and chyle granules]on the measurement of plasma ammonia by enzymatic assay method[glutamic dehydrogenase(GLDH)method]and dry chemistry method.Methods According to the Clinical and Laboratory Standards Institute(CLSI)EP7-A2 guideline,clinical plasma samples were collected,and basic samples with high and low concentrations were prepared.GLDH method and dry chemistry method were used to measure plasma ammonia respectively,and the relative deviation(high value samples)and absolute deviation(low value samples)of plasma ammonia determination results between interference samples and basic samples were calculated.The allowable deviation standard of the Royal College of Pathologists of Australasia(RCPA)(±3μmol/L for plasma ammonia≤30μmol/L,±10%for plasma ammonia>30μmol/L)was used as the clinical acceptable standard.Results Different concentrations of Hb did not interfere with the high and low value samples of plasma ammonia determined by dry chemistry method,and all the deviations were within the allowable deviation range.Hb had negative interference on the high and low value samples of plasma ammonia determined by GLDH method,and the degree of interference increased with the increasing of Hb concentrations.Bil had positive interference on the low value samples of plasma ammonia determined by dry chemistry method,when Bil≥184.4μmol/L,it had exceeded the allowable deviation range.There was no interference on the high value samples.Different concentrations of Bil had negative interference on the low value samples of plasma ammonia determined by GLDH method.For the high value samples of plasma ammonia,when Bil≥246.2μmol/L,it had negative interference on GLDH method.Chyle had no interference on the high value samples of plasma ammonia determined by dry chemistry method.There was positive interference in the chyle concentration of 612 FTU,and there was negative interference in the chyle concentration of 1534 FTU.Different concentrations of chyle had negative interference on the samples with low value samples of plasma ammonia determined by GLDH method.For the high value samples of plasma ammonia,except the chyle concentration of 306 FTU,the other chyle concentrations had negative interference.Conclusions The anti-interference ability of dry chemistry method to Hb,Bil and chyle is better than that of GLDH method,but these interfering substances will affect the repeatability of the 2 methods.