比较两种不同预处理法的尿液有机酸分析在遗传代谢性疾病筛查和诊断

Urine Organic Acids Analysis by Two Different Pretreatments for Screening and Diagnosis of Inborn Errors of Metabolism

目的:比较两种不同预处理法的尿液有机酸分析在遗传代谢性疾病筛查和诊断中的应用。方法:留取本院内分泌代谢科80例遗传代谢病高危患儿和80例同年龄段正常儿童尿液,分别经尿素酶预处理法和有机酸萃取预处理法处理后用GC-MS检测尿代谢产物,进行疾病诊断、代谢产物的定性、半定量及抗干扰性分析。结果:尿素酶预处理法共诊断15例代谢性疾病及1例肾小管重吸收障碍,有机酸萃取预处理法诊断出13例代谢性疾病;尿素酶预处理法能检测有机酸、氨基酸、糖、醇及嘧啶类等多种代谢产物,有机酸萃取预处理法仅能检测到有机酸;有机酸萃取预处理法对有机酸的检测值及抗干扰性都要高于尿素酶预处理法。结论:尿素酶预处理法适用于临床不能确诊的遗传代谢病的筛查;有机酸萃取预处理法则适用于临床高度怀疑为有机酸病的诊断。

Objective：To compare the use of urine organic acids analysis by two different pretreatments, urease and organic acids extraction pretreatments, for screening and diagnosis of inborn errors of metabolism （ IEM ） , so as to provide guidance for clinical decision-making on diagnostic options. Methods：80 fresh urine specimens from high-risk children of IEM and another 80 from healthy children were collected. The urine specimens, after pretreatment with urease （urease pretreatment method） and ethyl acetate extraction （extract pretreatment method） respectively, were subjected to tests of urine metabolic products by capillary gas chromatography/mass spectrometry （GC/MS）. Diagnosis of IEM, qualitative and semi-quantitative analysis and anti-interference between these two methods were performed. Results： Urease pretreatment method yielded confirmed diagnosis of IEM in 15 cases and tubular reabsorptiou disorder in 1 case, in contrast to IEM in 13 cases by extraction pretreatment method. Urease pretreatment method also successfully detected a variety of metabolic products such as organic acids, amino acids, galactose, galactitol, glycerol and uracils,whereas only organic acids could be detected with extraction pretreatment method. Compared with urease pretreatment method, extraction pretreatment was useful to high-level organic acids, and was with better anti-interference property. Concluslon：Urease pretreatment method may be suitable for screening IEMs that were clinically uncertain, while extraction pretreatment method can be useful for diagnosis of highly suspected cases.