2021 · Journal of clinical virology : the official publication of the Pan American Society for Clinical Virology · open access
Use of dried blood spot samples for SARS-CoV-2 antibody detection using the Roche Elecsys ® high throughput immunoassay
Mulchandani et al.
The finding, in our words
Dried blood spots showed 89% sensitivity and 100% specificity against plasma for SARS-CoV-2 antibodies, but the limit of detection was 30-fold higher and sample quality varied markedly by phlebotomist. For decentralised screening programmes, this relative insensitivity suggests capillary blood collection may be preferable.
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.
The study validated a semi-quantitative protocol for Epstein-Barr virus serology using dried blood spots, demonstrating 98.8% sensitivity and 96.5% specificity compared to paired venous serum samples. The successful validation in a self-sampling cohort confirms the suitability of this patient-centric microsampling approach for large-scale seroprevalence studies and decentralised trials.
Capillary samples collected using dried blood spots and Mitra microsamplers showed strong agreement with venous plasma for quantifying IgG antibodies against most vaccine-preventable diseases. Sensitivity was high for the majority of pathogens, though the study noted that antibody stability declined at room temperature over time, favouring cold storage for longer durations.
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.