Collection and processing of blood samples dried on paper for microassay of Newcastle disease virus and avian influenza virus antibodies.

A practical method for collection and processing of dried whole blood samples on filter paper was developed to facilitate large-scale testing programs for Newcastle disease virus and avian influenza virus antibodies. A modified paper punch was used to cut and place dried blood samples simultaneously in a standard 96-well microlate for elution of antibody. Twelve eluted samples were simultaneously transferred to another microplate for the hemagglutination-inhibition (HI) microtest. Similar HI titers were obtained with simultaneously collected serum and dried blood samples. Minor differences were not considered of practical importance in diagnostic serologic studies. Dried blood titers were not markedly affected by method of drying (37 C for 2 hours or 26 C for 4 hours), by storage for 24 hours before drying, or by storage of dried samples at 4 C for 28 days or 30 C for 14 days. Blood dried on paper was a satisfactory sample for assay of HI antibodies to Newcastle disease virus and avian influenza virus.