Assay Defender® Cat. No. #180

Assay Defender® is a ready-to use assay diluent for reduction of interference caused by HAMA (human anti-mouse antibodies), rheumatoid factors, nonspecific binding, cross-reactivities and matrix effects.

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Total HAMA and Interference Blocker

Ready-to use assay diluent for reduction of interference caused by HAMA (human anti-mouse antibodies), rheumatoid factors, nonspecific bindingcross-reactivities and matrix effects. Assay Defender® is particularly suitable for human or animal specimens containing HAMA (human anti-mouse antibodies), AAA (anti-animal antibodies) or other high affinity antibodies.

Assay Defender® can be used for different applications such as ELISA, lateral flow assays or bead-based assays. Examples are shown here.

For research use only, not for diagnostic use.

Reasons for interference

Interference in immunoassays can cause false positive and false negative results in routine testing.

Reasons for the increasing prevalence of different kinds of interference are for example:

  • ageing population
  • increasing number of patients with:
    • chronic autoimmune diseases
    • allergic and inflammatory diseases
  • an improved limit of detection in modern assays
  • more applications of sandwich-assay formats

Interferences can be classified due to their biochemical reasons and impact on assay performance.

  1. Interference caused by antibodies from patient samples
    e.g. HAMA (human anti-mouse antibodies), HAAA (human anti-animal antibodies), heterophilic antibodies and rheumatoid factors from patient samples
  2. Interference caused by endogenous components of the sample
    e.g. albumins, complement, lysozyme, fibrinogen, α-1 Antitrypsin, atypically high lipid-, salt- or sugar concentrations as well as atypical viscosities
  3. Interference caused by assay components
    Assay components - like fluorescent or enzymatic labels - can cross-react with substances from the sample or change binding properties of the assay antibodies

In contrast to conventional HAMA blockers, Assay Defender® enables effective elimination of all kinds of interference and helps to prevent false positive or false negative results.


Download Product Resources

 Assay Defender® Use
 Assay Defender® Matrix

Brand CANDOR Bioscience
Code 180 125

Product Flyers and Application Guides

 BIOAXXESS CANDOR Blocker Selection Guide NEW
BIOAXXESS CANDOR Product Application Guide
 CANDOR Products Brochure
 Assay Defender® Flyer NEW
 Assay Defender® Use NEW
 Assay Defender® LowCross-Buffer® Comparison Matrix NEW
 SafetyTector™ S NEW

Product Inserts and Data Sheets

Assay Optimizers

 Assay Defender® NEW
 LowCross-Buffer® ​​​​​Mild
 LowCross-Buffer® Strong
 LowCross-Buffer® Animal-free/Protein-free
 LowCross-Buffer® ​​​​​Mild Animal-free/Protein-free
 LowCross-Buffer® ​​​​​Strong Animal-free/Protein-free
 LowCross® HRP-Stab
 LowCross® HRP-Stab Animal-free/Protein-free
 LowCross® HRP-Stab Mild Animal-free/Protein-free
 LowCross® HRP-Stab Strong Animal-free/Protein-free
 Sample Buffer
 Sample Buffer Animal-free/Protein-free
 Sample Buffer IHC

Covid-19 Inactivation and Dilution Buffer

 SafetyTector™ S NEW


 The Blocking Solution 
 PlateBlock™ NEW


 Antibody Stabilizer TRIS
 Antibody Stabilizer TRIS Animal-free/Protein-free
 Antibody Stabilizer PBS
 Antibody Stabilizer PBS Animal-free/Protein-free
 Liquid Plate Sealer®
 Liquid Plate Sealer® Animal-free
 HRP-Protector™ Animal-free/Protein-free
 HRP-Protector™ TRIS
 HRP-Protector™ TRIS Animal-free/Protein-free
 HRP-Protector™ PBS
 HRP-Protector™ PBS Animal-free/Protein-free

Standard Buffers (ready-made)

 Coating Buffer pH 7.4 
 Coating Buffer pH 9.6 
 Stripping Buffer 
 Washing Buffer ReadyTector®
 Washing Buffer TRIS
 Washing Buffer TRIS IHC
 Washing Buffer PBS 
 Washing Buffer PBS IHC

All-in-One Western Blotting Solution

 ReadyTector® Anti-Mouse
 ReadyTector® Anti-Rabbit

Tool boxes

 Blocking Sampler Package with BSA Block
 CANDOR Starter Package
 CANDOR Starter Package IHC


 Interference and HAMA problems
 IVD Technology Article
 Long-term stabilization of assay components
 Optimisation of assays: Interference in immunoassays recognize and avoid 
 SARS-CoV-2 antigen tests: safety for less than 5 cents per test 
 Specificity, positive predictive value and validation statistics in the context of CoViD-19
 The Appropriate Blocker — A Short Overview
 The right strategy saves much costs