In this document, we report results from 2 distributions of the SUAC pilot blood spot materials and the first 2 SUAC proficiency testing (PT) challenge panels.
We prepared a set of pilot SUAC DBS calibrators by dividing 1 unit of hematocrit-adjusted blood into 7 portions for SUAC enrichment at 0, 1.
The challenge panel for the first SUAC PT event contained 4 members of the pilot set of SUAC calibrators (specimens 3831-4) and 1 specimen from a DBS pool made of nonenriched hematocrit-adjusted blood from a single donor (specimen 3835).
The 5-specimen panel for the second PT event contained 3 members from the set of SUAC DBS calibrators (specimens 4832-4) and 1 each of DBS specimens from nonenriched and SUAC-enriched portions of a single unit of hematocrit-adjusted blood (Specimens 4831 and 4835, respectively).
An instruction page, a data report form, and a questionnaire pertaining to SUAC screening practices were enclosed with every PT specimen panel.
First, systems must be put in place to be sure there is no mix-up in the sample extracts during recombination of SUAC and amino acid/ acylcarnitine extracts.
The combined result of SUAC and tyrosine appears to be definitive for Tyr-I.
We prepared DBS for SUAC calibration, recovery, stability, and imprecision studies as follows: aliquots of pooled whole blood were spiked with SUAC to achieve final concentrations of 0, 5, 10, 20, 50, and 100 [micro]mol/L, then spotted on filter paper (Whatman ProteinSaver 903) and dried overnight at room temperature.
Sample preparation entails a parallel work-up of eluates from the same DBS that contain either amino acids and acylcarnitines or SUAC.
Wetransferred the methanol eluates to another round-bottom 96-well plate, leaving the residual filter paper discs for subsequent elution of SUAC for 30 min at 65 [degrees]C by addition of 100 [micro]L acetonitrile/water/formic acid solution (80:20:0.
After extraction of SUAC from the leftover dried filter paper spots, the eluates were transferred to another round-bottom 96-well plate and dried under heated (40 [degrees]C) nitrogen for approximately 7 min.
We performed method optimization for the detection of SUAC by selected reaction monitoring (SRM) by infusing a 10 [micro]mol/L solution of SUAC and its internal standard as hydrazones at 0.