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HAMA Blocker: Human Anti-Mouse Antibody (HAMA) Interference

ELISA plate TRU Block

TruBLOCK logo

The Most Powerful HAMA Blocker against Immunoassay Interference


Blockers are used in ELISA and Lateral Flow assays to reduce interference from proteins in patient samples that could produce false results and an incorrect diagnosis. Download our Practical Guide to Immunoassay Blocking Reagents for a detailed overview on how blockers can be used to reduce non-specific binding in immunoassays.

Immunoassay blocking reagents guide
Immunoassay Blocking Reagents Guide

Example Application - Original TRU Block

TRU Block, the most powerful active blocker on the market today, actively blocks Heterophilic Antibody (HA) interference in immunoassays including, but not limited to, Human Anti-Mouse Antibody (HAMA) interference. Now, TRU Block outperforms a competitor's active blocker when tested against samples containing Rheumatoid Factor.

Seven different HAMA/RF samples were tested at varying concentrations and in two commercial ELISA assays. In all testing of HAMA/RF samples with blockers being added to sample diluent buffer, original TRU Block performed equal to or better than the competitor's active blocker.

Illustrated in the graph below is performance of original TRU Block when tested with Rheumatoid Factor (RF) Control Serum(Cat.# A12916H-2). The control serum created a false positive interference signal in a commercial CA19-9 Immunoassay. The interference could not be reduced by Mouse IgG or Rabbit IgG. In this case, only the active blockers were effective.

TRUBLOCK tested with Rheumatoid Factor (RF) control serum

What is Heterophilic antibody Interference?
  • Heterophilic antibodies are a group of human antibodies against animal IgG.  Ha interference is a well known interference factor in diagnostic assays, often causing false positive results.

  • The most known Heterophilic antibody interference is HaMa.  Ha to other animals such as Goat (HaGa), Sheep (HaSa), Rabbit (HaRa), etc. may also cause false results.

  • The frequency of such interference is low, but the false results have significant impact on the quality and competitiveness of the diagnostic assays as well as on the lives of those individuals who have been falsely diagnosed.

What is the difference between TRU Block and Mouse IgG?

TRU Block
Mouse IgG
  • Active Blocker
  • Passive Blocker
  • Uses a proprietary active mechanism to inhibit HAMA
  • Inhibits HAMA by serving as antigens of HAMA
  • Works well on HaMa as well as other types of HA
  • Effective on HaMa but not on other types of HA
  • Much lower concentration is needed than Mouse IgG (5-20 times less)
  • Higher concentration is needed than TRU Block

For more information on TRU Block please contact us.
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