Microsampling

Microsampling is the collection of biological sample volumes, typically of ≤50 µl, to determine drug/metabolite/biomarker levels. This enhances animal welfare and supports the 3Rs (Replacement, Reduction and Refinement) with fewer animals used, reduced blood loss and reduced warming. The animals are exposed to less stress and shorter test periods, due to the refined procedure. Improved toxicokinetic profiles increase data accuracy. 

Reduced volume also benefits human testing, primarily through the convenience of home testing kits, especially for patients in remote areas. Unlike dried blood spot (DBS) testing, microsampling encompasses approaches such as plasma microsampling, technologies simplifying collection of fixed-volume dried blood samples, skin microsampling and reverse iontophoresis. 

There is also potential for real-time or automated biomarker monitoring with hollow microneedles. One of the main challenges with this miniaturization is protocol standardization; therefore, recruitment of specialized professionals is vital for accurate diagnosis or analysis.

Microsampling is not suitable for larger molecules; for example, proteins may have differing concentrations depending on the region analyzed.