NAAT performance is more variable because of the greater instability of nucleic acids, but mostly, it reached similar diagnostic accuracy. Infant diagnoses using both RNA and DNA are feasible; however, RNA tests tend to suffer from reduced specificity. DAPT secretase Hepatitis viruses, many of the Herpes virus family, measles, and rubella also perform well with serological tests, with sensitivities and specificities of > 90%. NAATs seem promising, although more evaluations are needed, particularly for HCV and HEV. Dengue serology performed on DBS is clearly suitable for seroprevalence studies, although it is less clear for the diagnosis of acute primary and acute secondary infections. Dengue serotyping is epidemiologically important and can also be successfully performed from DBS.

43,139 DBS also play a key role in the diagnosis of parasitic infections. Detection of malaria by PCR using in-house methods is generally superior to microscopy. Most studies report sensitivities of > 94% and specificities of > 99%.56,58,140,141 Because of the prevalence of filariasis in remote settings, filter paper has been used in the diagnosis and investigation of epidemiology and response to eradication programs. Using commercially available assays, sensitivities of > 90% may be achieved.62,66 Leishmaniasis, cysticercosis, and giardiasis have proved to be less promising in the few studies that have evaluated DBS compared with a recognized gold standard.75,81,83 Serological tests for leptospirosis, treponemal infections, and some rickettsia have yielded excellent results,90,92,94 whereas others, such as brucellosis, have been less successful.

89 The selection of pathogens that may perform well on filter paper is dependent on several important factors, crucially the presence and quantity of serological markers and nucleic acids in the blood at the time of sample collection, their stability on filter paper, and the elution method that maximizes test performance with DBS. There are several key advantages of using filter paper over the traditional specimens of whole blood or serum. Many of the pathogens discussed above are most common in remote and resource-poor settings with limited access to advanced diagnostic facilities. Filter paper obviates the need for a cold chain to preserve specimens in transport to a central laboratory, thus enormously increasing the accessibility of these tests.

Filter paper is generally cheap (although some of the treated papers, such as FTA, are very expensive), requires only a small sample volume, and needs minimal technical expertise Batimastat to perform. These factors are likely to make sample collection more acceptable to the patient and less of a burden for the health system, and th
Approximately 400 million people worldwide are chronic carriers of hepatitis B virus (HBV) [1].