Efficiency of recovery of antibodies from blood spots. Comparison of OD obtained from paired plasma and blood spot eluates (each at an equivalent of 1:000 dilution) where blood spots were stored for 2 days (a,c) or 2 weeks at ambient temperature and RH (b,d). Samples were assayed for antibodies to MSP-119 (a,b) and MSP-2 (c,d). Aliquots of 8 hyperimmune plasma samples were mixed with equal volumes of erythrocytes, spotted on 3 MM paper and dried overnight. The lines in a,c are the best fit least square straight lines, calculated recovery 99%. The dashed lines in c and d represent the least-squares best fit lines for the recoveries shown.