Neurocysticercosis: validity of ELISA after storage of whole blood and cerebrospinal fluid on paper

Cysticercosis is an infestation of Cysticercus cellulosae. When it occurs i n the brain, chronic neurological complications can ensue, most commonly se izures. Neurocysticercosis is usually diagnosed by neuroimaging, a techniqu e not available in most endemic countries. Hence immunological tests are va luable for diagnosis and epidemiological surveys. We evaluated the suitabil ity of paper for storing blood and cerebrospinal fluid (CSF) until subseque nt testing by enzyme-linked immunosorbent assay (ELISA), by testing whole b lood samples on filter paper from 305 patients and CSF samples from 117 pat ients stored on ordinary white typing paper and on filter paper. Optimal pr eservation of biological samples is achieved when whole blood is stored on filter paper, CSF on white paper, and when samples are frozen within 1 week after collection. Our results could improve diagnostic capabilities and fa cilitate epidemiological surveys in endemic countries where immunodiagnosti c tests cannot be rapidly performed because of inadequate laboratory infras tructure.