Capillary earlobe blood may be used for RNA isolation, gene expression assays and microRNA quantification
Wehmeier & Hilberg
The finding, in our words
Capillary earlobe blood (20 µl) from adults yielded RNA expression results comparable to venous blood for four mRNAs and microRNA‑126. This microsampling approach may enable gene expression profiling in newborns, children and patients requiring repeated sampling or with bleeding disorders.
A paraphrase to the Library’s standard, never the abstract. The source is one link away and is always the authority.
This study validated a method requiring only 10 microlitres of serum and found high agreement between fingerstick capillary samples and venous serum for monitoring twelve antibiotics. The results suggest capillary serum sampling is a feasible, minimally invasive alternative that avoids the haematocrit effect associated with whole blood microsampling.
A 2025 review maps 28 microsampling devices, from dried spots and volumetric absorptive tips to upper-arm liquid capillary collectors, and names what a laboratory must control before their results are used: the haematocrit effect in non-volumetric dried samples, interstitial fluid from finger milking, volume, haemolysis and transport stability. Regulators on both sides of the Atlantic ask for the same two things, a device the patient can use safely and a sample fit for the test.
In 91 children and adults, capillary C-peptide taken with the TAP device matched venous sampling with 100% sensitivity and specificity for a clinically relevant level, 200 pmol/L or above, with r = 0.996. 63% preferred it to a needle against 7% who preferred the needle, and same-day bruising was 5.5% versus 34.8% after a venous draw.
An IQ Consortium position paper from sponsor scientists positioning patient-centric sampling as the enabling technology for decentralised trials, and stating that a bridging study against conventional sampling “has quickly been established as a regulatory expectation”.
Maass et al., Clinical and Translational Science · source ↗
Two home-use capillary blood collection kits for HbA1c measurement produced results within 5% of venous values for 96% to 99% of samples across different shipping conditions. The kits were easy to use and yielded comparable results to venous specimens for both paediatric and adult participants, supporting their use in decentralised clinical research and care.