Establishment of an Asia-Pacific Dried Blood Spot External Quality Assurance Program

Introduction: An expansion in laboratories using dried blood spots (DBS) for newborn screening and chronic condition monitoring, combined with limited availability of Centres for Disease Control DBS external quality assurance (EQA) material for non-US participants and quarantine regulations, prompted the development of an Asia-Pacific DBS-EQA program. The Royal College of Pathologists of Australasia Quality Assurance Programs (RCPAQAP), in conjunction with the Sweat Testing Advisory Committee, present results for the 2019 pilot DBS-EQA program.
Methods: The DBS program material is prepared from blood spiked with analytes at six linearly related levels. Each level is provided in duplicate as a set of twelve DBS samples sent as one shipment annually to enrolled participants. Initial analytes are thyroid stimulating hormone (TSH), immunoreactive trypsinogen (IRT), tyrosine (tyr), phenylalanine (phe) and 17 hydroxy progesterone (17OHP). Initial analytical performance specifications (APS) were established as ±10%, with all-laboratory median used as the measure of central tendency. Participant results are compared for imprecision, bias and linearity using standard RCPAQAP reporting.
Results: Five Australasian laboratories enrolled for the first cycle of this program. The initial results demonstrated linearity within and between laboratories for TSH (1.0-350mIU/L), IRT (8-220ug/L), phe (20-2020ug/L), tyr (35-1600ug/L) and 17OHP (5.0-150nmol/L). Bias was assessed and >80% of laboratories were within the APS for TSH, IRT, phe and tyr, confirming the validity of these performance limits.
Conclusions: We have successfully established a DBS-EQA program for the Asia-Pacific region that fulfils an emerging local need and opportunity for harmonisation. Future developments include analyte expansion and clinical case interpretation.