Here the sensitivity is very low that is the reason why the condition happened. The error resulted are not highly specific. The reason for binding is because the unnecessary binding occurred.
Agglutination between saline and O antigen shows that there is a contamination which is acting as an agglutination.
The contamination can present as an antiserum or as an antigen or may be in chemical or physical agents and they are termed as the responsible factors for agglutination.