探讨采用流动注射串联质谱法(MS/MS)联合检测精氨酰琥珀酸(Asa)与瓜氨酸(Cit)水平在新生儿精氨酰琥珀酸尿症(ASLD)筛查中的价值。

回顾性分析2014年1月1日至2024年3月21日，在南京市新生儿筛查中心采用第一代MS/MS试剂盒检测Cit水平累计筛查621 686例新生儿中，确诊的ASLD患儿1例；以及选择2024年3月至2025年8月采用第二代MS/MS试剂盒联合检测Asa和Cit水平累计筛查87 729例新生儿，其中确诊ASLD 1例。对筛查阳性患儿采用基因检测，并结合临床数据评估Asa在ASLD筛查中的价值。

87 729例新生儿中，共有8例初筛Asa阳性，其中1例经召回复查确诊ASLD。Asa的初筛阳性率为0.01%，敏感度为100.00%，特异度为99.99%，阳性预测值为12.50%。该例确诊患儿Asa水平升高，而Cit在参考区间内。

Asa用于ASLD筛查具有较好的筛查效能，可在Cit处于参考区间时提示风险，有望降低单用Cit的漏诊风险。

To explore the value of combined detection of arginylsuccinic acid (Asa) and citrulline (Cit) levels by flow injection tandem mass spectrometry (MS/MS) in the screening of neonatal arginylsuccinic aciduria (ASLD).

A retrospective analysis was conducted. Among a total of 621 686 newborns screened using the first-generation MS/MS kit by detecting Cit level at the Nanjing Neonatal Screening Center from January 1, 2014 to March 21, 2024, 1 case of ASLD was diagnosed. From March 2024 to August 2025, a total of 87 729 newborns were screened using the second-generation MS/MS kit by detecting Asa and Cit levels, and 1 case of ASLD was diagnosed. Genetic testing was adopted for screen-positive children, and the clinical data were comprehensively evaluated to determine the value of Asa in screening for ASLD.

Among 87 729 newborns, 8 were initially screen-positive for Asa, of whom 1 was confirmed to have ASLD after recall and confirmatory testing. The initial screening positivity rate for Asa was 0.01%, with a sensitivity of 100.00%, specificity of 99.99%, and positive predictive value of 12.50%. In the confirmed case, Asa level was elevated, whereas Cit remained within the reference range.

Asa demonstrates favorable screening efficacy for ASLD. It can indicate risk even when Cit is within the reference range and may help reduce the risk of missed detection when using Cit alone.