Approximately 7% of the sera tested to determine the presence of rubella-specific antibodies by the hemagglutination inhibition test demonstrated abnormal patterns of reactivity, rendering the test unreadable. Another 3% of sera were shown to have false-positive titers as high as 1:128. When these abnormally reacting and false-positive sera were heated at 56 degrees C for 30 min after chemical ...

A hemagglutination method employing tanned human O erythrocytes sensitized with purified Group A streptococcal polysaccharide has been developed to measure A polysaccharide antibody in antistreptococcal rabbit and human sera. The reaction of sensitized RBC with known Group A streptococcal rabbit antisera, inhibition of hemagglutination with A polysaccharide, and abolition of hemagglutination an...

A sensitive immunoassay procedure for the detection of the thrombopoietic-stimulating factor (TSF) has been developed. This procedure Is similar to the hemagglutination-inhibition (HAl) technique that is available for erythropoietin. For the production of TSF, sheep were made thrombocytopenic by the Injection of antiplatelet serum. TSF from sheep sera was partially purified by column chromatogr...

Hemagglutination inhibition, enzyme-linked immunosorbent assay (ELISA), and passive latex agglutination were used to test 495 human serum samples for determination of rubella immunity. Overall agreements for immune status were as follows: hemagglutination inhibition versus ELISA, 94.7% (469 of 495); hemagglutination inhibition versus passive latex agglutination (1:10 dilution), 99.2% (491 of 49...

The New York City Health and Nutrition Examination Survey (NYC HANES) was a population based sample of New York City adults collected in 2004. To determine seroprevalence to 2009 H1N1 antibody, as well as viruses from prior pandemics, a 400 person subsample of repository serum was selected for inclusion in the study, representing persons who were 23 or older in 2004. All specimens were tested b...

To estimate population attack rates of influenza A(H1N1)pdm2009 in the Southern Hemisphere during June-August 2009, we conducted several serologic studies. We pooled individual-level data from studies using hemagglutination inhibition assays performed in Australia, New Zealand, and Singapore. We determined seropositive proportions (titer ≥40) for each study region by age-group and sex in pre- a...