72 Table 4 Summary of studies evaluating DBS for parasites other than malaria PCR testing on DBS for visceral selleck screening library leishmaniasis (Leishmania infantum) in immunocompromised patients before therapy was evaluated against bone marrow microscopy in a small series of patients, yielding a sensitivity of 75%.75 PCR on DBS was significantly more sensitive than microscopy and culture of peripheral blood. Campino and others75 suggest a possible role for PCR on DBS as an initial screening test, potentially avoiding more invasive bone marrow aspiration. Seroprevalence studies for echinococcosis, fascioliasis, cysticercosis, and toxoplasmosis performed well on DBS.76�C82 However, antibodies to cysticercosis decreased rapidly when stored on filter paper.
81 Detection of exposure to giardiasis suffered from low specificity, possibly reflecting cross-reactivity or long-term persistence of antibodies.83,84 Bacteria. There have been few studies evaluating the use of filter paper to diagnose or determine the seroprevalence of bacterial infections compared with viruses and parasites (Table 5). Table 5 Summary of studies evaluating DBS for bacteria The success of using both serum and DBS to screen for leprosy is dependent on the bacillary burden, with multibacillary patients more readily identified.85�C87 The commercially available Serodia Leprae particle agglutination test (Fujirebio, Tokyo, Japan) using DBS had 97.5% concordance with serum for patients of any bacillary burden.88 Interestingly, the sensitivity of capillary DBS taken from skin smear sites, such as the earlobe, was slightly but significantly higher compared with venous DBS and serum.
This result may reflect a higher concentration of antibodies at the site of infection compared with circulating antibodies.85 Brucella antibodies were eluted from filter paper with difficulty, and correlation coefficients with serum were modest.89 However, correlation coefficients are not valid statistical tests for comparison of diagnostic methods.46 Serological tests for other bacterial pathogens, including syphilis, yaws, leptospirosis, and some rickettsial diseases, performed well on DBS and could be stored successfully for sufficient periods of time to allow transport to a laboratory for analysis.90�C95 Practical Aspects And Implications Of Using Dbs Samples Compared With Traditional Methods Some of the key neglected but practical aspects that should be taken into account when using DBS samples are discussed below (Figure 2).
Figure 2. Practical aspects and implications of using DBS. NA = nucleic acid. Filter paper. There are many different filter paper brands available consisting of 100% cellulose, and they vary in thickness and pore size. Although many manufacturers produce cards, Cilengitide only two brands are US Food and Drug Administration (FDA) -approved for human whole-blood collection (Whatman 903 and PerkinElmer [Beaconsfield, UK] 226 filter papers).
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