Development of Certified Reference Material for Amino Acids in Dried Blood Spots and Accuracy Assessment of Disc Sampling

Abstract

To achieve the measurement reliability of amino acids used as diagnostic markers in clinical fields, establishing a reference measurement system is required, in which certified reference materials (CRMs) are an essential step in the hierarchy of measurement traceability. This study describes the development of dried blood spot (DBS) CRMs for amino acid analysis with complete measurement traceability to the International System of Units (SI). Six essential amino acids—proline, valine, isoleucine, leucine, phenylalanine, and tyrosine—were analyzed using isotope-dilution liquid chromatography–mass spectrometry (ID-MS). For minimizing measurement bias and uncertainty overestimation, whole spots with 50 μL of whole blood were adopted in the certification. The between-spot homogeneities by whole spot sampling were lower than 2.1%. The relative expanded uncertainties of the six amino acids in the developed DBS CRMs were lower than 5.7% at 95% confidence. The certified values are traceable to SI through both gravimetric preparation and the primary method in certification, ID-MS. Comparison among DBS testing laboratories revealed discrepancies between the whole spot and disc sampling methods. The actual sampling volume was accurately estimated by weighing, which revealed the possibility of underestimation in routine DBS testing. The candidate CRMs can support the standardization of DBS testing for amino acids through the qualification and validation of many kinds of measurement procedures to compensate the measurement bias caused by matrix-specific sampling error.

Harmonization of distributed multi‐center analysis based on dried blood spot reference materials supporting the screening of neonatal inherited metabolic disorders

“…The standardization of quantification data is critical to the reliability and measurement traceability in the screening of neonatal inherited metabolic disorders, [15][16][17] and developing DBS reference materials is the base step in such terms. A set of DBS reference materials with great traceability can play a significant role in DBS-based screening, providing secondary calibration for specific measuring systems, 18 which is very limited across the world. Moreover, most neonatal screening reference materials contain only a few kinds of amino acids, 18,19 and cannot fully reflect the metabolic disorders of the newborns.…”

“…A set of DBS reference materials with great traceability can play a significant role in DBS-based screening, providing secondary calibration for specific measuring systems, 18 which is very limited across the world. Moreover, most neonatal screening reference materials contain only a few kinds of amino acids, 18,19 and cannot fully reflect the metabolic disorders of the newborns.…”

Availability of Reference Materials for Improving Quality of Life within Scientific and Industrial Framework

“…COVID -19 pandemic scenarios introduced technical needs to have remote diagnosis means with the support of sample collection, storage and transportation outside clinical premises. Initiatives on RM development in such situations are reported for the purpose of controls of tests[25]. A typical case study during COVID -19 pandemic periods illustrates the significance of RM as experimental controls of testing viral infections.…”