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.
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.
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.
Guardian-collected capillary dried blood spots were feasible for home monitoring of lamotrigine, and for carbamazepine and valproic acid when conversion factors were applied, with only 4 of 190 comparisons risking a conflicting dose decision and negligible risk of patient harm. Levetiracetam DBS showed high variability against plasma and is recommended only for checking nonadherence, not for dose adjustment.
The validated LC-MS/MS method showed similar pharmacokinetic profiles for albendazole and its metabolites across plasma, whole blood, dried blood spots and Mitra microsamples from hookworm-infected adolescents, supporting microsampling for paediatric pharmacokinetic studies. Mitra extraction proved more robust than dried blood spots during validation and is recommended for future albendazole pharmacokinetic work, despite higher albendazole sulfone concentrations observed in both microsampling devices compared with wet matrices.