What might cause a false-negative result in agglutination reaction?

A false-negative result in an agglutination reaction may occur due to insufficient antigen or antibody concentration, leading to incomplete binding. Additionally, improper sample preparation, such as inadequate mixing or incorrect temperature, can hinder the reaction. The presence of interfering substances, like high levels of lipids or proteins in the sample, may also obscure agglutination. Lastly, using outdated or improperly stored reagents can affect the sensitivity of the assay.