Newborn screening is a public health care program worldwide to prevent patients from critical illness or conditions. Tandem mass spectrometry allows multiplex, inexpensive, and rapid newborn screening. However, mass spectrometry used for newborn screening to date is not able to separate peaks of compounds with similar m/z, which could lead to false-positive results without additional second-tier tests, such as fragmentation. We experienced three neonatal cases with high levels of markers, octanoylcarnitine and octanoylcarnitine/decanoylcarnitine ratio used to pick up possible cases of medium-chain acyl-CoA dehydrogenase (MCAD) deficiency. The babies were born consecutively in a maternity hospital. Their second acylcarnitine profiles were normal, and the genetic tests for ACADM were negative. Analysis of samples extracted from their first Guthrie cards where blood was not stained also showed peaks equivalent to octanoylcarnitine and decanoylcarnitine, indicating contamination. Environmental surveillance in the maternity ward suggested that essential oils used there might contain the contaminated compound. LC-HRMS/MS and in silico analysis revealed that false-positive results might be due to contamination with the essential oils in Guthrie cards, and causal agents were sphinganine (d17:0) and 2-[2-hydroxyethyl(pentadecyl)amino]ethanol. Thus, health care providers should be cautioned about use of essential oils when collecting blood samples on Guthrie cards. False-positive results can waste costly social resources and cause a physical and psychological burden for children and parents.

新生儿筛查是一项全球性的公共卫生保健计划，旨在防止患者患上严重的疾病或状况。串联质谱法可进行多重，廉价且快速的新生儿筛查。但是，迄今为止，用于新生儿筛查的质谱仪无法分离出具有相似m / z的化合物峰，这可能导致假阳性结果，而无需进行其他第二级测试（例如裂解）。我们经历了三例高水平标记物，辛酰基肉碱和辛酰基肉碱/癸酰基肉碱比率的新生儿病例，以发现可能的中链酰基辅酶A脱氢酶（MCAD）缺乏症。婴儿在妇产医院连续出生。他们的第二个酰基肉碱轮廓正常，并且对ACADM进行了基因检测是负面的。分析从他们的第一张Guthrie卡中提取的样品，这些样品没有被染色，也显示了相当于辛酰基肉碱和癸酰基肉碱的峰，表明存在污染。产科病房的环境监测表明，那里使用的精油可能含有受污染的化合物。LC-HRMS / MS和计算机分析结果表明，假阳性结果可能是由于Guthrie卡中的精油污染所致，其诱因是Sphinganine（d17：0）和2- [2-羟乙基（十五烷基）氨基]乙醇。因此，在Guthrie卡上采集血液样本时，应警告医疗保健人员使用精油。假阳性结果可能浪费昂贵的社会资源，并给孩子和父母带来身心负担。