Barker RH Jr, Banchongaksorn T, Courval JM, Suwonkerd W, Rimwungtragoon K, Wirth DF, 1992. A simple method to detect Plasmodium falciparum directly from blood samples using the polymerase chain reaction. Am J Trop Med Hyg 46 :416–426.
Snounou G, Viriyakosol S, Jarra W, Thaithong S, Brown KN, 1993. Identification of the four human malaria parasite species in field samples by the polymerase chain reaction and detection of a high prevalence of mixed infections. Mol Biochem Parasitol 58 :283–292.
Contamin H, Fandeur T, Bonnefoy S, Skouri F, Ntoumi F, Mercereau-Puijalon O, 1995. PCR typing of field isolates of Plasmodium falciparum. J Clin Microbiol 339 :44–51.
Paul RE, Hackford I, Brockman A, Muller-Graf C, Price R, Luxemburger C, White NJ, Nosten F, Day KP, 1998. Transmission intensity and Plasmodium falciparum diversity on the northwestern border of Thailand. Am J Trop Med Hyg 58 :195–203.
Singh B, Cox-Singh J, Miller AO, Abdullah MS, Snounou G, Rahman HA, 1996. Detection of malaria in Malaysia by nested polymerase chain reaction amplification of dried blood spots on filter papers. Trans R Soc Trop Med Hyg 90 :519–521.
Singh B, Bobogare A, Cox-Singh J, Snounou G, Abdullah MS, Rahman HA, 1999. A genus- and species-specific nested polymerase chain reaction malaria detection assay for epidemiologic studies. Am J Trop Med Hyg 60 :687–692.
Magesa SM, Mdira KY, Farnert A, Simonsen PE, Bygbjerg IC, Jakobsen PH, 2001. Distinguishing Plasmodium falciparum treatment failures from re-infections by using polymerase chain reaction genotyping in a holoendemic area in northeastern Tanzania. Am J Trop Med Hyg 65 :477–483.
Farnert A, Arez AP, Correia AT, Bjorkman A, Snounou G, do Rosario V, 1999. Sampling and storage of blood and the detection of malaria parasites by polymerase chain reaction. Trans R Soc Trop Med Hyg 93 :50–53.
Brockman A, Paul RE, Anderson TJC, Hackford I, Phaiphun L, Looareesuwan S, Nosten F, Day KP, 1999. Application of genetic markers to the identification of recrudescent Plasmodium falciparum infections on the northwestern border of Thailand. Am J Trop Med Hyg 60 :14–21.
Panteleeff DD, John G, Nduati R, Mbori-Ngacha D, Richardson B, Kreiss J, Overbaugh J, 1999. Rapid method for screening dried blood samples on filter paper for human immunodeficiency virus type 1 DNA. J Clin Microbiol 37 :350–353.
Akane A, Matsubara K, Nakamura H, Takahashi S, Kimura K, 1994. Identification of the heme compound copurified with deoxyribonucleic acid (DNA) from bloodstains a major inhibitor of polymerase chain reaction (PCR) amplification. J Forensic Sci 39 :362–372.
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To evaluate the effect of long-term storage of sample filters on the sensitivity of polymerase chain reaction (PCR) detection of malaria, 252 blood spots from patients with microscopically confirmed Plasmodium falciparum malaria were analyzed and stratified by storage duration. The spots were collected between 1996 and 2000 on filter paper and stored at room temperature. A Chelex-based method was used to extract the DNA. Unexpectedly, after the first purification, the sensitivity of the PCR from recently stored samples was low and showed progressively increased with time storage (P = 0.003, by chi-square test for linear trend). This suggested that PCR inhibitors were easier to dissolve from the more recent blood spots (< 4 years old) than from blood spots ≥4 years old, thus leading to a time-dependent increase in PCR sensitivity. However, if DNA was purified again (when the first PCR result was negative), the cumulative sensitivity was not influenced by storage duration. This indicated that length of storage is not a critical issue providing purification is sufficient.