Comparison of capillary dried blood spot and capillary microtubes with venous immunoglobulin G levels for routine diagnostics
Boland et al.
The finding, in our words
The study found that capillary microtube samples showed perfect correlation, R 1.00, and narrow limits of agreement with venous blood for IgG monitoring, making them a viable alternative. Dried blood spots showed only moderate correlation, R 0.77, and broad limits of agreement, which the authors state makes them unsuitable for routine diagnostics.
A paraphrase to the Library’s standard, never the abstract. The source is one link away and is always the authority.
The study demonstrated that qPCR-based epigenetic immune cell counting from capillary dried blood spots agreed with venous blood and conventional flow cytometry in healthy donors, and then identified lymphopenia, neutrophilia and a lowered lymphocyte-to-neutrophil ratio in 103 COVID-19 patients versus 113 healthy controls, with naive B cell frequency tracking disease severity, suggesting that filter-paper blood collection could enable remote immune monitoring in home-isolated patients.
Capillary blood self-sampling showed near-perfect agreement with venous sampling for SARS-CoV-2 IgG detection, achieving a Cohen's kappa of 0.88. Samples remained stable at room temperature for seven days, and 38 of 39 participants successfully collected adequate volumes, supporting its use for decentralised serological testing.
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.
Dried VAMS and DBS samples collected at home and analysed after a median of three days showed poor agreement with standard venous or capillary blood for HbA1c monitoring. In contrast, wet VAMS samples analysed immediately demonstrated excellent agreement, indicating that sample drying and delayed analysis compromise reliability for decentralised HbA1c measurement.