Microsampling involves collecting a very small volume of blood (often 10–30 µL; ≤50 µL by convention) from a capillary puncture (finger-stick, heel-stick, or alternative sites). The drop of blood is absorbed onto a fixed-volume collection device or applied to a card, dries at room temperature, and is later eluted and analyzed in the lab.
Fixed volume collection offers a modern alternative to traditional venipuncture and hematocrit prone dried blood spot (DBS) sampling methods.
Further, conventional blood sample obtained through venipuncture can range from 5 to 10 mL, making it 500 to 1,000 times larger than a microsample. Venipuncture also requires trained staff, and cold-chain logistics when shipped.
But Microsampling is minimally invasive, only requires low-volume collection and can be used for remote collection—supporting decentralized trials, longitudinal sampling, and improved participant experience.
Capillary blood is a mixture of arterial and venous blood at the tissue exchange interface. Relative to venous plasma, capillary measures may show:
For many assays, equivalence can be established via method validation. Always confirm correlation and bias for your analyte and method before clinical or research adoption.
Sample Stability: Dried microsamples can remain stable for days or weeks at room temperature, but environmental factors may still affect certain analytes.
Hematocrit (HCT) Bias: Traditional DBS spot formation and analyte distribution can vary with HCT. Volumetric devices are designed to mitigate this by absorbing a fixed volume independent of drop size; nevertheless, labs should verify performance across expected HCT ranges.
Extraction Efficiency: Recovery depends on analyte chemistry (e.g., lipophilicity, protein binding) and matrix. Optimize extraction buffers/times per analyte.
User Technique: Standardize site warming, cleaning (often soap & water is preferred to alcohol for comfort/flow), discard first drop, avoid milking, and ensure correct drying/packaging.
Clinical Trials – Decentralized, patient-friendly sampling that may improve retention.
Therapeutic Drug Monitoring (TDM) – More frequent, lower-burden monitoring without venipuncture.
Pediatrics & Special Populations – Minimal sample volumes for vulnerable groups.
Population Health & Remote Studies – Enables data collection outside clinical settings.
Preclinical & Veterinary Research – As part of an international initiative aimed at improving the treatment of animals during medical screening, capillary microsampling was developed to address the 3Rs: Reduction, Replacement, and Refinement. This approach seeks to eliminate unnecessary harm to laboratory animals. The benefits of capillary microsampling extend beyond this goal, as it effectively reduces animal usage while supporting the principles of the 3Rs.
The rapid expansion of telemedicine and remote care pathways has accelerated adoption of finger-stick sampling. Labs now commonly ship at-home kits (including collection devices, lancets, and instructions). Participants collect, dry, and mail samples for analysis—supporting continuous programs like chronic disease monitoring and longitudinal serology.
Comfort tips: wash with soap and water (alcohol can constrict/dry skin), prick the side of the fingertip, select appropriate gauge/depth, discard the first drop, and avoid milking.
Microsampling offers a reliable, patient-friendly, and operationally efficient alternative to traditional blood collection. With proper validation, attention to hematocrit and extraction, and good collection technique, it can expand access, reduce costs, and support modern research and care. Contact us to explore how our devices and expertise can help you adopt microsampling technology effectively. Or to learn more click here.