Presoaking dried blood spot with water improves efficiency for small-molecule analysis

The current method of extracting small molecules from dried blood spots (DBSs) and liquid blood is similar. However, owing to their different physical characteristics, a modification of the extraction process for DBS is required. We propose a modified method involving presoaking in water that results in better extraction efficiency for small-molecule analysis than the conventional protein precipitation method. Using blood and DBSs from eight subjects, the similarities, recovery rates and extraction efficiencies of both methods were compared. Quantitative analysis showed that seven and six out of ten conditions for the modified method group exhibited almost 100% recovery and extraction efficiency rates, respectively, compared with the conventional method group. Taken together, the results suggest that a presoaking step is needed for efficient DBS analysis. METHOD SUMMARY This study describes the increased efficiency resulting from inclusion of a water addition step before small-molecule extraction from DBS when using the protein precipitation principle.