Sandwich Assays
Two site sandwich immunoassays can suffer from false positive results caused by heterophilic antibody interference. Heterophilic antibodies give rise to a false positive signal by bridging the capture and detection antibodies. Conventional blockers (e.g., mouse serum, mouse lgG, goat serum, goat lgG, and others) can eliminate some but not all of the interference. Heterophilic antibody interference which is not eliminated by conventional blockers is largely ignored.
HeteroBlock® is designed to pick up where conventional blockers leave off. HeteroBlock® contains active and passive blocking agents. The active agents have a high affinity for heterophilic antibodies. Thus, HeteroBlock® may reduce the incidence of false positive results.
HeteroBlock® is typically formulated into the sample diluent at various concentrations to establish the working concentration for each antibody pair.
HeteroBlock® offers the following advantages:
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Contains specific and non-specific blockers
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Contains active and passive agents
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Composed of purified protein from animal sources
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Blocks false positives
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No effect on true positives
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Proven across multiple platforms
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Yields a stable assay signal
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µg quantities are used to block
HeteroBlock® was used to eliminate false positive signals under the following conditions:
Human Serum, Lot 8507, CRP Negative
HeteroBlock® at
500 µg/mL
Goat Anti-Human CRP Coated Latex Particles
Agglutination Result
+2,3
50 µL
50 µL
0 µL
+2
50 µL
50 µL
1 µL
50 µL
50 µL
2 µL
+2
50 µL
50 µL
3 µL
+1
50 µL
50 µL
4 µL
+1
50 µL
5 µL
50 µL
Negative