Short-Term Stabilities of 21 Amino Acids in Dried Blood Spots

Abstract

BACKGROUND: Dried blood spots (DBSs) have potential use in remote health applications for individual and population diagnosis, and can enable epidemiological surveillance for known and unknown diseases. The preparation and transportation of DBSs from remote settings often exposes these cards to extreme environmental stress that may impact the quality of the diagnostic data. Given these risks, it is essential to investigate the individual stabilities of biomarkers in DBSs. This paper details the stability of routinely-analyzed amino acids (AAs) on DBSs under environmental conditions that simulate a global health workflow. METHODS: The extractions of 21 AAs from three sets of DBSs prepared on cellulose and cotton filter paper were optimized for quantitation by dansylation-UPLC/MRM-MS. The effects of sunlight exposure, temperature, humidity, and storage time were studied. RESULTS: The AAs were stable in DBSs after 4-hour sunlight exposure, and after storage at -20 and 4 o C for 30 days. At 25 and 40 o C, only 7 AAs showed significant concentration decreases over time, while 2 showed concentration increases. The changes were accelerated by high humidity. Histidine was the least stable AA under the conditions tested. CONCLUSIONS:This study provides quantitative data on the short-term stabilities of 21 AAs in DBSs on cellulose and cotton-based filter paper, under environmental conditions that simulate a globalhealth workflow. These results highlight the importance of assessing the stability of clinically-relevant biomarkers in DBSs. Based on the measured stabilities, we recommend that higher-temperature and high-humidity storage of DBS samples be avoided for AA analysis in remote health applications.

Improved Dried Blood Spot-Based Metabolomics: A Targeted, Broad-Spectrum, Single-Injection Method

“…Our results demonstrate that most metabolites were stable for the first month of storage, regardless of condition. Similar results have been reported for the stability of amino acids, acylcarnitines, and vitamin D in DBS stored for one month at room temperature with desiccants [30,31]. Besides these routinely analyzed metabolites, in our study, we expanded the stability analysis to other key metabolites in DBS, and for up to one year of storage.…”

Dried Blood Spots for Global Health Diagnostics and Surveillance: Opportunities and Challenges

“…Temperature and humidity conditions directly affect the ability to detect specific amino acids and metabolites routinely measured for newborn screening. 115 , 116 Gene transcriptomics analysis of newborn DBS was more consistent if samples were stored at temperatures less than −20°C immediately after specimen acquisition, 111 with time and temperature imparting various degrees of degradation for specific mRNA profiling targets and housekeeping genes. 112 Lower temperatures is not the solution for all analytes; three polyunsaturated fatty acids used to screen newborns for neural development and visual function were found to have significant degradation after 10 days of storage at −28°C, with a high degree of intraindividual variability, when measured from umbilical blood dried on Ahlstrom 226 cards.…”

Use of Dried Blood Spot Specimens to Monitor Patients with Inherited Metabolic Disorders

“…The stability of DBS methionine is particularly poor and at room temperature will degrade by at least 50% in six months. High humidity and ambient temperature will also increase the rate of degradation [30,31]. Results from our own investigations demonstrate that methionine is unstable even at room temperature after 3 days of storage (Figure 1).…”

“…Most amino acids were shown to be stable in DBS specimens (Whatman 903 and PerkinElmer 226) during a 4 h exposure to sunlight. However, methionine is unstable and showed a relatively high extent of degradation by~25% [30]. The stability of DBS methionine is particularly poor and at room temperature will degrade by at least 50% in six months.…”