{Reference Type}: Journal Article
{Title}: Volumetric dried blood spots for determination of phosphatidylethanol: Validation of a liquid chromatography tandem masspectrometry method and clinical application.
{Author}: Beck O;Barroso M;Hermansson S;Widén C;Wallin C;Nilsson-Wallmark C;de Bejczy A;
{Journal}: Drug Test Anal
{Volume}: 0
{Issue}: 0
{Year}: 2024 Apr 25
{Factor}: 3.234
{DOI}: 10.1002/dta.3695
{Abstract}: Phosphatidylethanol (PEth) measurement in whole blood samples is established as a specific alcohol biomarker with clinical and forensic applications. Establishment of dried blood spots (DBSs) as a specimen for PEth determination offers several advantages and was the focus of this work. A liquid chromatography tandem mass spectrometry method using a 96-well format for sample preparation was developed and validated. PEth was extracted from DBSs by using isopropanol containing PEth-d5 as internal standard. The blood sampling used a commercial volumetric DBS device having a phosholipase D inhibitor incorporated to stop continuous PEth formation. The method quantified PEth in the range of 0.05-10 μmol/L, with a bias and imprecision of less than 15%. In a clinical study (n = 25) using fingerprick blood, the volumetric device offered more precise quantifications (CV 4.6%) compared with the Whatman 903 Protein Saver card device (CV 16.6%). In another clinical study (n = 48), the use of dried venous and capillary blood, and liquid venous blood was compared under real-life conditions with samples sent by postal service. The capillary and venous DBS samples gave identical results while the liquid blood gave slightly higher values. Calculation of elimination half-life (PEth 16:0/18:1) in 31 cases based on two consecutive samples with 2-9 days in between gave results (mean 6.2 days) that agree with literature but several cases with values over 10 days. In conclusion, this study demonstrates that volumetric DBS is a valid specimen for determination of PEth blood concentrations, offering several advantages.