Diluted dried blood drops on filter paper were compared with serum
samples
as a specimen source for qualitative anti-HAV antibody determination by
ELISA. A
total of 298 serum
samples and dried blood drops were collected from a population of healthy
adolescents
(15·3±1·2 years old). The prevalence of anti-HAV antibody
obtained by testing serum samples
was 7·7% (95% CI: 4·8–10·1). Compared with serum
sampling the sensitivity and specificity of
diluted dried blood drops were 91·3 and 99·3%. The positive
and
negative predictive values
were 91·3 and 99·3%, respectively, and the likelihood ratios
of
positive and negative results
were 91 and 0·09. It is proposed that this test represents a reliable
procedure for anti-HAV antibody testing.