Related Experiment Video
Updated: Jan 25, 2026

Fabrication of Zero Mode Waveguides for High Concentration Single Molecule Microscopy
Published on: May 12, 2020
Heterophilic antibody interference in a non-endogenous molecule assay: an apparent elevation in the tacrolimus
Sara Altinier1, Mariacristina Varagnolo, Martina Zaninotto
1Department of Laboratory Medicine University-Hospital of Padova, Italy. sara.altinier@sanita.padova.it
Background:
In drug monitoring assays the most common interferences are due to hematocrit, other drugs or their metabolites, while the interference by heterophilic antibodies has been reported only when measuring endogenous molecules. In the present paper a heterophilic antibody interference in the tacrolimus measurement is described.
Methods:
Samples from a patient treated with tacrolimus were analyzed on RxL Dimension analyzer. Ranging drug concentrations from 49 to 12.5 microg/L, even after the interruption of the treatment, confirmation analysis were performed using heterophilic blocking tubes before tacrolimus measurement on the same analyzer, then testing the samples on V-Twin System, finally incubating the samples with chlorophenol red beta-d-galactopyranoside, beta-galactosidase, polyclonal mouse IgG, protein A and Protein G resin.
Results:
The elevated tacrolimus concentrations were due to the presence of an interference attributable to heterophilic antibodies, as confirmed by treating the samples with heterophilic blocking tubes and protein G resin.
Conclusions:
a) The interference caused by heterophilic antibodies can be found not only in immunoassays measuring endogenous molecules, but also in those for exogenous molecules; b) the pre-treatment sample procedure, which represent the main difference between the methods affected and unaffected by the interference, is a fundamental step in removing the antibodies responsible of the interference.
More Related Videos
Related Concept Videos
Elevation of Intermediate Points on Vertical Curves
Apparent Weight
Consider a person standing on a bathroom scale inside an elevator. If the scale is accurate at rest, its reading equals the...
Freezing Point Depression and Boiling Point Elevation
The boiling point of a liquid is the temperature at which its vapor pressure is equal to ambient atmospheric pressure. Since the vapor pressure of a solution is lowered due to the presence of nonvolatile solutes, it stands to reason that the solution’s boiling point will subsequently be increased. Vapor pressure increases with temperature, and so a solution will require a higher temperature than will pure solvent to achieve any given vapor pressure, including one...
Interference and Diffraction
RNA Interference
This process occurs naturally in cells, often through the activity of genomically-encoded microRNAs. Researchers can take advantage of this mechanism by introducing synthetic RNAs to deactivate specific genes for research or therapeutic purposes. For example, RNAi could be used...
Apparent Weight and the Earth's Rotation
For an object on the Earth's equator, the net centripetal force that accounts for its rotation is the Earth's pull towards its center, or the weight minus the normal force that prevents it from piercing into the Earth's surface....

