Abstract
The use of blood collected and dried on filter paper - dried blood spot (DBS) - have started in the middle of the 20th century. DBS sampling can be performed outside care facilities, by capillary puncture, transported in a simple and safe manner by mail, and used with most laboratory methods for antibodies, antigen, or nucleic acids testing. The benefits of this blood collection and transport means explain the growing interest for DBS in the recent years. DBS sampling has shown clinical utility to improve in vitro diagnostics of infectious diseases in hard to reach populations, key populations and people living in low-income countries. DBS can be used at all stages of the therapeutic cascade: screening, confirmation, quantification of nucleic acids, resistance genotyping. Numerous studies dedicated to HIV, viral hepatitis B and C diagnosis using DBS have been reported. The performance of HIV RNA testing on DBS to identified virological failure on therapy is high but not optimal due to the dilution of dried blood in the elution buffer that reduces the analytical sensitivity and due to the contamination by intracellular HIV DNA. Good sensibility and sensitivity have been reported for infant HIV diagnosis and diagnosis of hepatitis B and C using DBS. Variabilities in the pre-analytical steps - including DBS preparation and nucleic acid extraction - limit inter-laboratory comparisons. Too few manufacturers have proposed technical notes for using their assays on DBS and very few assays have pursued regulatory approval for in vitro diagnostic on DBS. Regulatory approvals remain exceptional. Despite these limitations, DBS sampling is a main tool to improve access to infectious disease diagnosis worldwide and is now recommended by international recommendations.