Dried Blood Spots (DBS): A suitable alternative to using whole blood samples for diagnostic testing of visceral leishmaniasis in the post-elimination era

Prakash Ghosh; Rajashree Chowdhury; Md Abu Rahat; Faria Hossain; Nur E Arpha; Mojca Kristan; Matthew Higgins; Ahmed Abd El Wahed; Yasuyuki Goto; M M Towhidul Islam; Susana Campino; Mary Cameron; Malcom S Duthie; Rashidul Haque; Dinesh Mondal

doi:10.1371/journal.pntd.0011680

Dried Blood Spots (DBS): A suitable alternative to using whole blood samples for diagnostic testing of visceral leishmaniasis in the post-elimination era

PLoS Negl Trop Dis. 2023 Oct 20;17(10):e0011680. doi: 10.1371/journal.pntd.0011680. eCollection 2023 Oct.

Authors

Affiliations

¹ Nutirition and Clinical Services Division, International Centre for Diarrhoeal Disease Research, Banladesh, Dhaka, Bangladesh.
² Genetic Engineering and Biotechnology, BRAC University, Dhaka, Bangladesh.
³ London School of Hygiene and Tropical Medicine, University of London, London, United Kingdom.
⁴ Institute of Animal Hygiene and Veterinary Public Health, University of Leipzig, Leipzig, Germany.
⁵ Laboratory of Molecular Immunology, Department of Animal Resource Sciences, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan.
⁶ Department of Biochemistry and Molecular Biology, University of Dhaka, Dhaka, Bangladesh.
⁷ HDT Bio, Seattle, Washington, United States of America.
⁸ Emerging Infections and Parasitology Laboratory, International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh.

Abstract

Background: Serum or whole blood collection, processing, transport and storage still present significant challenges in low resource settings where mass surveillance is required to sustain disease elimination. Therefore, in this study, we explored the diagnostic efficacy of dried blood spots (DBS) as a minimally invasive and potentially cost-effective alternative sampling technique to whole blood sampling procedures for subsequent detection of Leishmania donovani antibodies or DNA.

Methodology and principal findings: Archived serum, DNA samples from whole blood of visceral leishmaniasis (VL) cases and healthy controls, and DBS from corresponding cases and controls, were used. Both molecular and serological assays were optimized to detect L. donovani antibodies or DNA in DBS elute and results were compared against those obtained with whole blood. Serological assays (both rK28 ELISA and rK39 ELISA) of DBS samples showed sensitivity and specificity of 100% and had excellent agreement with results from whole blood samples (kappa value ranged from 0.98-1). Bland-Altman analysis of OD values from rK28-ELISA with DBS elute and patients' serum showed an excellent agreement (ICC = 0.9) whereas a good agreement (ICC = 0.8) was observed in the case of rK39-ELISA. However, qPCR and RPA of DBS samples had a diminished sensitivity of 76% and 68%, respectively, and poor agreement was observed with the whole blood samples.

Conclusion: Our results demonstrate that DBS offer excellent diagnostic efficiency for serological assays and represent a viable alternative to whole blood sampling procedures.

Copyright: © 2023 Ghosh et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

MeSH terms

Antibodies, Protozoan
Antigens, Protozoan
DNA
Diagnostic Techniques and Procedures
Dried Blood Spot Testing / methods
Humans
Leishmaniasis, Visceral* / diagnosis
Leishmaniasis, Visceral* / epidemiology
Sensitivity and Specificity

Substances

Antigens, Protozoan
Antibodies, Protozoan
DNA

Grants and funding

The funding was granted by the Swedish International Development Cooperation Agency (Sida,GR-01455), Sweden and Rainy Day Grant Fund under ‘Young investigator’s award’, International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b) to PG. The authors alone are responsible for the views expressed in this manuscript. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.