Comparison of Capillary Microsampling and Venous Blood for Multi-Pathogen Serosurveillance

Why It Matters

DBS enables cost‑effective, scalable immunity monitoring in low‑resource settings, accelerating vaccine‑program decisions without cold‑chain constraints.

Key Takeaways

• DBS matches plasma for six of seven vaccine‑preventable diseases.
• Sensitivity drops below 80% for pertussis across matrices.
• Frozen storage (-20°C) preserves antibodies up to 90 days.
• Ambient storage maintains stability only up to 30 days.
• Mitra VAMS reduces hematocrit bias compared with filter paper.

Pulse Analysis

Serosurveillance remains a cornerstone for assessing population immunity and guiding immunisation strategies, yet traditional venous blood collection imposes logistical burdens—trained phlebotomists, immediate processing, and stringent cold‑chain requirements. In low‑resource environments, these constraints limit the frequency and geographic reach of surveys, prompting interest in capillary microsampling techniques such as dried blood spots (DBS). By simplifying collection and transport, DBS can expand surveillance coverage while reducing costs, provided analytical performance matches that of plasma.

The recent comparative study evaluated DBS collected on conventional filter paper and on Mitra volumetric absorptive microsamplers against paired venous plasma using a validated fluorescent bead‑based multiplex immunoassay. Results demonstrated high concordance for diphtheria, tetanus, measles, mumps, rubella and varicella, with over 93% of observations falling within the 95% limits of agreement and sensitivities above 95%. Pertussis remained an outlier, showing sensitivities between 72% and 78%, indicating a need for assay refinement. Stability testing revealed that frozen storage at –20 °C retained antibody integrity for up to 90 days, whereas ambient storage was reliable only through 30 days, after which sensitivity and specificity declined markedly.

These findings have practical implications for public‑health agencies seeking to implement large‑scale serosurveillance in remote regions. Deploying Mitra VAMS can mitigate hematocrit‑related variability and ensure consistent volume collection, while short‑term room‑temperature storage offers flexibility when cold‑chain logistics are unavailable. Policymakers can now consider integrating DBS‑based protocols into routine monitoring, accelerating detection of immunity gaps and informing targeted vaccination campaigns. Future work should focus on enhancing pertussis assay sensitivity and establishing standardized elution procedures to further solidify DBS as a gold‑standard alternative to venous sampling.