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Blockers

Immunoassay blockers are used in diagnostic assays to reduce non-specific binding and other interference that can lead to false-positive results. Specifically, antibody interference from human anti-mouse antibodies (HAMA), rheumatoid factor (RH), and heterophilic antibodies (HA) are a major concern in both paired monoclonal sandwich assays and competitive assays. In IgM detection assays, IgG antibodies which are present in 10-15x higher concentrations than IgM can also reduce assay sensitivity due to their sheer abundance. Specialized blockers are required to reduce antibody interference from HAMA, HA, RF and IgG to ensure an assay's accuracy and improve its sensitivity.

immunoassat blockers

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Blockers Products (25)

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Name Type Format Host/Source Isotype Tested Apps Unit Catalog SDS COA Request Sample
TRU Block 3 Purified Confidential N/A Blo GM A66803H View SDS View COA Order A Sample
TRU Block 2 Purified Confidential N/A Blo GM A66802H View SDS View COA Order A Sample
TRU Block Purified Confidential N/A Blo GM A66800H View SDS View COA Order A Sample
Mouse IgG-Protein A 30-40mg/ml Purified Mouse Serum N/A Blo GM A66190M-NA View SDS View COA Order A Sample
Mouse IgG Protein A (proclin) Purified Mouse Serum N/A Blo GM A66189M View SDS View COA Order A Sample
Mouse IgG (ca Cut)(10-20mg/mL) Purified Mouse Serum N/A Blo GM A66187M View SDS View COA Order A Sample
Mouse IgG (azide Free) Purified Mouse Serum N/A Blo GM A66186M-NA View SDS View COA Order A Sample
Mouse IgG (9-13mg/mL) Purified Mouse Serum N/A Blo GM A66186M View SDS View COA Order A Sample
MOUSE IGG-PROTEIN A 50-55MG/ML Purified Mouse Serum N/A Blo GM A66185M-NA View SDS View COA Order A Sample
Mouse IgG Protein A 50-55 Mg/m Purified Mouse Serum N/A Blo GM A66185M View SDS View COA Order A Sample
Mouse IgG Protein A 22-28mg/mL Purified Mouse Serum N/A Blo GM A66181M View SDS View COA Order A Sample
BSA, Standard Powder Purified Bovine N/A EIA,IHC,WB GM A64801B View SDS View COA Order A Sample
Elisa IgM Assay Diluent I Purified Goat N/A EIA ML 8120 View SDS View COA Order A Sample
TRU Block Ultra Purified Confidential N/A Blo,EIA,LF GM 8000 View SDS View COA Order A Sample
Goat anti Human IgG+IgM+IgA Hl HRP Goat N/A IHC,WB ML W99591G View SDS View COA Order A Sample
Goat anti Human IgG (Fc) HRP Goat N/A EIA,IHC,WB ML W99036P View SDS View COA Order A Sample
Goat anti-human IgG (h+l) FITC Goat N/A EIA,IEP MG W01262FL View SDS View COA Order A Sample
Goat anti Human IgG (H&L) Alexa Fluor 488 Goat N/A EIA,IEP MG W01260AF View SDS View COA Order A Sample
Goat anti Human IgG (Fc) Aff.Pur. Goat N/A EIA MG W01252G View SDS View COA Order A Sample
GOAT ANTI-HUMAN IGG (FC)-DILUT Purified Goat N/A Nep,TIA,IgM ML L15408G View SDS View COA Order A Sample
Goat anti-human IgG (Fc) Monospecific Goat N/A EIA,IEP,Nep,TIA ML L15406G View SDS View COA Order A Sample
Coating Stabilizer & Block Buf Liquid - N/A N/A ML J16430D View SDS View COA Order A Sample
Mouse-FREE IgG Purified, Liquid Cell Culture N/A Blo MG BN1300 View SDS View COA Order A Sample
K-Block Purified Cell Culture N/A Blo MG BN1200 View SDS View COA Order A Sample
Goat anti-human IgG(Fc) Aff.Pur. Goat N/A N/A MG W66040G View SDS View COA Order A Sample

TRU Block – Targeting all Heterophile Interferences

TRUE Positive Result

active hama blocker table

Meridian's Blockers Range

  • Designed to remove human-anti-mouse interference (HAMA), heterophilic interference (HA), and rheumatoid factor (RF) interference.

  • Suitable for double mouse monoclonal and competitive immunoassays.

  • Effective at low concentrations (100x-1,000x less than passive blocking agents such as animal serums).

tru block performance data

tru block animal igg range

IgG Blockers for IgM Detection Assays

Competition between IgG and IgM antibodies for antigen binding sites can significantly reduce assay sensitivity in IgM detection assays. In addition, IgG can form immune complexes with Rheumatoid Factor (RF) and compete with specific IgM for substrate binding sites. Removal of IgG and RF-IgM can be accomplished by pre-treating the patient specimen with goat anti-human IgG or IgM diluent.

tru block reduce-igg-competition

FAQs: Immunoassay Interference Blockers

Immunoassays used for human in vitro diagnostics (IVD) typically use animal-derived antibodies to recognize specific disease markers. Some patients have antibodies in their blood that can react with animal antibodies in the immunoassay and cause a false result. Although the frequency of these interferences is low, false-positive results have a significant negative impact on the quality and competitiveness of a diagnostic assay as well as on the lives of those individuals who have been falsely diagnosed.

Human anti-mouse antibodies (HAMA) is the common antibody interference which causes both positive and negative interferences in two-site mouse monoclonal antibody-based assays.

No. HAMA only represents one type of heterophilic antibody (HA) interference – others include HA to animals such as goat (HAGA), sheep (HASA), and rabbit (HARA) which can cause false results when antibodies originating from these animals are used in immunoassays. In addition to HA there is another class of interference called Rheumatoid factor (RF), which is an autoantibody that reacts with the patient’s own immunoglobulin (Ig) and can cross react with animal Ig, similar to HA/HAMA
interference.

Rheumatoid factor is an autoantibody (usually IgM) directed against the Fc portion of IgG. It is common in people with rheumatoid factor, occurring in about half of all people with the disease, but about 1 in 20 people without rheumatoid arthritis can also have high levels and is more common in elderly patients.

RF, similar to heterophilic antibodies, has the potential to cause falsely elevated test results by cross-linking the assay antibodies, even in the absence of analyte, most often via binding to the Fc-part of assay antibodies. RF can react against different species of IgG, including human and rabbit.

Our recommendations are: a) use the species of the blocker the same as the host of the capture or detection antibody; 2) use at a concentration of Mouse or Goat IgG equivalent to ten times the concentration of the MAb/PAb being used in the assay. (e.g. if 5ug/mL of Ab/conjugate, add 50ug/mL of animal IgG)

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Have questions about a product? Want to learn more about Meridian’s molecular or immunoassay reagent portfolio? We want to hear from you!


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