A unique offer of robust, cost-effective ELISAs for the screening of residues in milk, meat, seafood and honey

New generation binding assays are now able to detect entire families of drugs in different matrices. Antibodies are engineered to be more cross-reactive than usual; receptors are used instead of conventional antibodies; competitors are synthesized in order to compete with a broader range of analytes.

Broad-range assays are therefore able to detect a number of structural-related contaminants and mixtures of contaminants as well, but they cannot identify which analyte is actually present.
Besides, it is almost impossible to obtain broad-range binders with controlled cross-reactivity patterns. Typically, some cross-reagents show very high affinity for the binding-site of the ligand, while others have lower cross-reactivity. For this reason, when a broad-range analysis leads to a positive result, it is not possible to know which is the contaminant nor its "real" concentration.

In a theoretical example, one antibody has 100% cross-reactivity for the analyte A, 20% for the analyte B and 250% for the analyte C.
A certain sample is revealed as positive, corresponding to 100 ppb of analyte A equivalents.
This could mean that:

  • the sample contains 100 ppb of A
  • the sample contains around 500 ppb of B
  • the sample contains around 40 ppb of C.

It is clear that the identification and the quantification of drug residues in animal products is almost impossible when using broad-range assays.
For these reasons most of Tecna broad-range classical test kits have been combined with a new, cost-effective, faster format: B ZERO.
B ZERO is a unique line of microplate immunoassays for chemical contaminants with no need to run any calibrator apart the “zero” standard. Proper calibration curves, which B/Bo values are optimized for each kits batch, have been established (“master curves”). Once obtained the ratio between each sample absorbance (B) and the zero standard absorbance (Bo), the B/Bo value of each sample can be interpolated onto the master curve to obtain the result. B ZERO assays are supposed to be run in single replicate.

The overall cost per analysis dramatically drops since no wells are spent to run the calibrators and every sample can be run in one single well.