Use of filter paper disks for hepatitis A surveillance.
BACKGROUND
Venous blood collection is a cumbersome and uncomfortable procedure during hepatitis A surveillance. Collection of capillary blood by finger prick is an alternative method.


OBJECTIVE
To evaluate the reactivity of capillary blood/anti-hepatitis A virus (HAV) IgG stored on filter paper disks for detection of anti-HAV antibody.


METHODS
Venous blood specimens were collected from healthy individuals. Simultaneous capillary blood specimens obtained by finger prick were stored on filter paper disks. A reference standard of anti-HAV IgG in known concentrations was spotted on filter paper disks. The reactivities of anti-HAV IgG and capillary blood specimens eluted from filter paper disks were tested by blocking ELISA for detection of anti-HAV antibody. The results were evaluated by comparing optical density (OD) and neutralization values with those obtained for WHO anti-HAV IgG stored in liquid phase and homologous venous blood specimens, respectively.


RESULTS
Among both venous and capillary-blood specimens stored for 10 days, percent neutralization shown by the same 46 specimens was > 50 and that of the same 3 specimens was < 50, indicating anti-HAV positivity and negativity, respectively. There was significant correlation between the OD values displayed by anti-HAV IgG from liquid phase and that eluted from filter paper disk (p < 0.01). Sixteen serum specimens stored for a period of 2 months showed results similar to those of the corresponding filter paper disk elutes.


CONCLUSIONS
Use of filter paper disks could be a suitable choice for pre- and post-immunization collection of blood specimens during hepatitis A surveillance.
Chitambar
S D
SD
Hepatitis Department, National Institute of Virology, Pune.
Chadha
M S
MS
D001431:Bacteriological Techniques; D005260:Female; D005374:Filtration; D006506:Hepatitis A / Q000097:blood* / Q000175:diagnosis* / Q000276:immunology; D006508:Hepatitis Antibodies / Q000032:analysis / Q000097:blood*; D006507:Hepatovirus / Q000276:immunology*; D006801:Humans; D008297:Male; D010209:Paper; D011159:Population Surveillance; D012016:Reference Values; D012680:Sensitivity and Specificity; D013048:Specimen Handling
D006508:Hepatitis Antibodies