Immunoassay Blockers:
Removing HAMA and HA Interference in Double Mouse Monoclonal Sandwich Assays

Immunoassay interference is a general term for substances that can change the outcome of an assay by causing a false positive or false negative test result. Examples of potentially interfering particles include endogenous antibodies such as heterophilic antibodies (HA) (e.g. HAMA) and rheumatoid factor (RF). Double mouse monoclonal assays and competitive assays are specifically prone to HA and RF interference and require a specialized blocker to ensure the assay’s accuracy.

Meridian has developed and validated a range of immunoassay blockers that are used in commercially approved assays to remove interference.

  • How HAMA Blockers Work

In double mouse monoclonal assays, a specific blocker is required to remove a particular type of HA interference called human anti-mouse antibodies (HAMA) and Rheumatoid Factor (RF). A HAMA blocker contains a specific binder directed against all types of heterophilic interference including HAMA and RF. Once bound to the interfering antibodies, TRU Block prevents further binding of HA to other assay components through steric hindrance.