Abstract
Dried blood spots (DBS) have advantages such as minimizing blood collection volume and the distress to neonate. DBS have been used for tandem mass spectrometry (MS/MS)-based newborn screening tests (NST) of amino acid (AA) and acylcarnitine. The Newborn Screening Quality Assurance Program (NSQAP) have been provided quality control (QC) materials for MS/MS, as DBS cards. The NSQAP is generally provided within 14 months of the shelf life and the recommended storage condition is at −10 °C to −30 °C. Previously, several accelerated degradation studies had been performed to determine the transportation stability and short-term stability of AAs and acylcarnitines in DBS. However, the experimental condition is markedly different to the storage condition. We performed long-term monitoring for the real-time stability of seven AAs and 14 acylcarnitines from three levels of 2012 NSQAP QC materials across a time period of 788 days. Arginine suddenly yielded a catastrophic degeneration pattern, which started around D300. When comparing this with previous accelerated degradation studies, methionine, tyrosine, citrulline, and acetylcarnitine did not show a remarkable measurand drift for the real-time stability, except for arginine. Our study showed that arginine would require intensive QC monitoring in routine practice, and should be used for the assessment of the stability in long-term storage of DBS samples for biobanking.
Highlights
Inborn errors of metabolism (IEM) are treatable disorders for which timely treatment is critical to prevent mortality and to improve the outcome [1,2,3]
We enrolled a total of six Newborn Screening Quality Assurance Program (NSQAP) quality control (QC) materials for amino acid (AA) consisting of Lot, Lot, and Lot, and materials for AC consisting of Lot, Lot, and Lot, respectively
Further trend analysis using other lots of NSQAP QC materials for AAs high should be performed for elucidating whether this pattern and trend are observed at similar times. These results indicate that there is a need for QC monitoring of MS/MS-based newborn screening test (NST), including Arg high, and, more intensive monitoring is required for Arg
Summary
Inborn errors of metabolism (IEM) are treatable disorders for which timely treatment is critical to prevent mortality and to improve the outcome [1,2,3]. The newborn screening test (NST) is helpful for early detection of IEM [4], and it has been performed annually for approximately 10 million neonates worldwide [5]. MS/MS-based NST is modified according to the laboratory’s demands [12]. These in-house modifications, which are categorized as laboratory-developed tests (LDTs) cause the difficulty of quality assurance (QA) and inter-laboratory comparison [13], because there are no reference methods of MS/MS-based NST [14]. The Centers for Disease Control and Prevention (CDC) have operated the Newborn Screening Quality Assurance Program (NSQAP) for quality management of NST [15]. The NSQAP have provided QA services including quality control (QC) materials to participating laboratories. The reliable QC materials with obtained values from NSQAP participating laboratories within a similar MS/MS method and instrumentation help to maintain QA by quantitative internal QC monitoring [8]
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