AnalyticalQuantification of multiple elements in dried blood spot samples

- A method for quantification of multiple elements from dried blood spots was established
- There was a good agreement with measurements in venous blood for most elements
- Element recovery was verified with spiked samples
- Contribution of element signal from the filter paper affects quantification of some elements
- Measurement of dried blood spot iron or potassium can be used to estimate sample hematocrit

BackgroundDried blood spots (DBS) is a unique matrix that offers advantages compared to conventional blood collection making it increasingly popular in large population studies. We here describe development and validation of a method to determine multiple elements in DBS.MethodsElements were extracted from punches and analyzed using inductively coupled plasma-mass spectrometry (ICP-MS). The method was evaluated with quality controls with defined element concentration and blood spiked with elements to assess accuracy and imprecision. DBS element concentrations were compared with concentrations in venous blood. Samples with different hematocrit were spotted onto filter paper to assess hematocrit effect.ResultsThe established method was precise and accurate for measurement of most elements in DBS. There was a significant but relatively weak correlation between measurement of the elements Mg, K, Fe, Cu, Zn, As and Se in DBS and venous whole blood. Hematocrit influenced the DBS element measurement, especially for K, Fe and Zn.ConclusionTrace elements can be measured with high accuracy and low imprecision in DBS, but contribution of signal from the filter paper influences measurement of some elements present at low concentrations. Simultaneous measurement of K and Fe in DBS extracts may be used to estimate sample hematocrit.