The best practice for preparation of samples from FTA？cards for diagnosis of blood borne infections using African trypanosomes as a model system

A comparison of five techniques was made. Detection from directly applied whole blood was less sensitive (35.6%) than whole blood which was subsequently eluted from the cards using Chelex？100 (56.4%). Better apparent sensitivity was achieved when blood was lysed prior to application on the FTA cards (73.3%) although this was not significant. This did not improve with subsequent elution using Chelex？100 (73.3%) and was not significantly different from direct DNA extraction from blood in the field (68.3%).Based on these results, the degree of effort required for each of these techniques and the difficulty of DNA extraction under field conditions, we recommend that blood is transferred onto FTA cards whole followed by elution in Chelex？100 as the best approach.Blood and buffy coat samples have been routinely collected on ordinary filter paper for analysis and detection of different blood pathogens [1-7]. Although collection of blood samples on filter paper for large scale sampling seems to be more convenient than other sampling procedures, such as in situ DNA extraction [2], filter papers are not suitable for long term storage, as they do not protect the sample from spoiling and degradation [8].Flinders Technology Associates (FTA) technology has improved upon this paper based system. The FTA？card has been designed to fix and store nucleic acids directly from tissues, allowing the collection and archiving of nucleic acids [9,10]. The FTA matrix is impregnated with protein denaturants that cause lysis of cells and any organism on contact. Moreover, these chemicals inhibit detritivores during drying to ensure the safe handling of cards without risk of biohazards [9,11]. FTA technology also includes chelating agents and a free-radical trap designed to deal with atmospheric pollutants, thus protecting the entrapped nucleic acids for at least six years at room temperature [11].FTA？cards have been used for blood storage [12,13], detecting bacterial pathogens [11,14], detectio