Comparison of two blood collection techniques for measles antibody detection in children.

ABSTRACT

BACKGROUND & OBJECTIVES: Though several seroprevalence and seroconversion studies have been conducted for measles using the filter paper haemagglutination inhibition (FPHAI), very few studies have compared the conventional serum HAI with the FPHAI. The present study was aimed at the evaluation of whole blood samples on filter paper as an alternative to serum specimens for detection of antibodies to measles virus. METHODS: Serum and whole blood samples soaked on filter paper were collected from 165 randomly selected healthy children in the age groups of 1-2 yr. HAI test was performed on both sets of samples and the results compared. RESULTS: Ninety samples that gave a titre of 8 or more by serum HAI also had titres of > or = 8 by FPHAI showing 100 per cent agreement between the two assays. Seventeen samples that had a serum HAI titre of 2 and 4 were missed by FPHAI due to the starting dilution of 8 of the latter. However, FPHAI gave no false positive results compared with serum HAI. INTERPRETATION & CONCLUSION: Collection of the FP samples by finger prick is more acceptable and requires less expertise than venepuncture. Thus, in spite of the small percentage of missed cases by the filter paper method, this technique of sampling was found to be a convenient and reliable alternative to venepuncture, for detection of measles virus antibody especially in large scale seroepidemiological studies.