Table 4.
Summary of studies evaluating DBS for parasites other than malaria
| Disease, assay type, and country | Ref. | Number of samples/filter paper type | Test | Sensitivity (%) | Specificity (%) | Notes |
|---|---|---|---|---|---|---|
| Lymphatic filariasis: Wb, Bspp serology and dipstick antibody test | 94 patients/ Whatman 903 | In-house EIA | 92 | 77 | ||
| India | 167 | |||||
| Ghana | 65 | 1,808 patients/Og4C3 paper | Og4C3 ELISA (Wb; Tropical Biotechnology) | 50.3 | 96.4 | |
| Sri Lanka | 62 | 60 patients/ Nobotu 1 | Og4C3 ELISA (Wb) | 97 | NR | |
| India | 63 | 30 patients/ Whatman No.3 | Og4C3 ELISA (Wb) | 76.6–93.3 | 100 | Time of the day at which samples are collected impacts sensitivity. |
| India, Egypt, Haiti, Kenya, Papua New Guinea, Sri Lanka | 64 | 188 patients/Whatman No.3 | Og4C3 ELISA (Wb) | NR | NR | |
| Egypt | 66 | 81 samples/filter paper (Tropical Biotechnology) | Filariasis (Wb and Bspp) CELISA (Cellabs) | 91 (Wb); 98 (Bspp) | NR | Based on a panel of known positives. |
| Uganda | 67 | 66 patients/Whatman 3MM | Brugia Rapid (Reszon Diagnostics) | 79 | NR | Significant cross-reactivity with other filarial infections.66,67 |
| Lymphatic filariasis: B. malayi, NAAT | ||||||
| Indonesia | 68 | 36 patients/ Whatman 3MM | In-house PCR and ELISA combination | 86 | NR | PCR-ELISA produced comparable results compared with DNA Detection Test Strips (Roche, Germany). |
| Malaysia | 69 | 21 patients/ Whatman 3MM | In-house PCR | NR | NR | |
| Mansonelliasis NAAT | ||||||
| Brazil | 168 | 12 patients/ Whatman paper | In-house PCR | NR | NR | PCR was able to distinguish between O. volvulus, M. ozzardi, and M. perstans. |
| Loa loa filariasis NAAT | ||||||
| Cameroon | 70 | 68 patients/ NR | In-house PCR | 96 | NR | High specificity. No cross-reactivity with other filarial species. Limit of detection 1 microfilaria/20 μL whole blood (as DBS). |
| HAT serology (card agglutination test) | ||||||
| Sudan | 71 | 100 patients/ NR | Micro-CATT (ITM Antwerp) | 91 | NR | |
| Central African Republic, Ivory Coast | 72 | 940 patients/ Whatman No.4 | Micro-CATT (ITM Antwerp) | 89.4–95.5 | 95.5–96.6 | Truc and others72 report rapid drop in sensitivity (67.8%) after 3 days without strict humidity control of paper. Ranges reported by Truc and others72 reflect testing at two different sites. |
| Chagas disease serology | ||||||
| Brazil | 74 | 6,222 patients/ Whatman No.1 | In-house ELISA, IF, and HA | ELISA, 78.1; IF, 69.2; HA, 64.6 | ELISA, 99.7; IF, 99.4; HA, 99.6 | |
| Brazil | 73 | 24 patients/ NR | Chagas Stat-Pak (ICT; Chembio Diagnostic Systems) | 100 | 100 | Chagas Stat-Pak performed on small sample size. More sensitive and specific than large-scale evaluation with serum. |
| Echinococcosis serology | ||||||
| Argentina | 76 | 479 patients/ Whatman No.1 | In-house ELISA | NR | NR | Coltorti and others76 report sensitivity of DBS to be similar to serum. |
| Uruguay | 78 | 1,149 patients/ Whatman No.1 | In-house ELISA | NR | NR | |
| China | 77 | 2,482 patients/ Whatman No.1 | In-house ELISA | 96 | 87 | |
| Visceral leishmaniasis NAAT | ||||||
| Portugal | 75 | 24 patients/ Whatman No.2 | In-house PCR | 71–75 | NR | 15/20 positive for patients not on treatment and 17/24 if patients on treatment included. Useful as an initial screening tool. |
| Fascioliasis serology | ||||||
| Bolivia | 79 | 68 patients/ Whatman No.1 | In-house ELISA | NR | NR | Samples missed on DBS had the lowest ELISA readings. Samples stored for 10 years at 4°C were successfully detected. |
| Giardiasis serology | ||||||
| Saudi Arabia | 84 | 147 patients/ Whatman No.4 | In-house ELISA | 72–96 | 39–98 | al-Tukhi and others84 reported ranges that depended on ELISA OD reading and final eluate dilution. Guimaraes and Sogayar83 had a high rate of false positives with ELISA. |
| Brazil | 83 | 133 patients/ Whatman No.1 | In-house IF; in-house ELISA | 82; 72 | 70; 39 | |
| Cysticercosis serology | ||||||
| Brazil | 80 | 151 patients/ Whatman No.4 | Qualicode Cysticercosis ELISA kit (Immunetics Inc.) | 80 | NR | Good agreement between serum and DBS. May be a useful initial screening test. Fall in sensitivity if filter paper was not frozen after 1 week storage. Ranges were caused by samples being processed at two sites using two methods. |
| Mexico | 81 | 305 patients/ Whatman No. 311 | In-house ELISA | 39–66 | 87–96 | |
| Toxoplasmosis serology (latex agglutination) | ||||||
| United Kingdom | 82 | 273 patients/ Whatman 903 | Eiken Toxoreagent Latex Agglutination | 98.8 | 100 | |
Bssp = Brugia malayi and B. timori; CATT = Card Agglutination Test for Trypanosomiasis; HAT = Human African Trypanosomiasis; IF = Immunofluorescence; Wb = Wucheraria bancrofti.