Diluents / Buffers FAQ

Frequently Asked Questions about Surmodics Assay Diluent / Buffers

Can Surmodics Assay Diluent be used for calibration controls?
Yes. In addition to diluting patient samples, Surmodics Assay Diluent is recommended for dilution of the standard curve and controls.

What are the causes of matrix interference?
Some matrix interference can come from endogenous substances and characteristics such as salt concentration, pH, and viscosity of the solution. Substances such as heterophilic antibodies (including human anti-mouse antibodies "HAMA" and rheumatoid factor "RF"), and anti-animal antibodies can play a more prominent role in matrix interference by non-specifically binding to the antibodies or analyte. While these causes of interference are diverse in nature, the Surmodics Assay Diluent minimizes the effect of these sources of interference.

Does Surmodics Assay Diluent work better with specific classes of heterophilic antibodies, such as IgG vs. IgM?
No. Surmodics Assay Diluent is a fully synthetic formulation and does not contain animal antibodies, and therefore, is not class specific to the heterophilic antibodies in the patient sample. Instead, we have developed a proprietary formulation that uses innovative blocking compounds to prevent weak binding interactions associated with non-specific binding.

Can I use Surmodics Assay Diluent for other dilutions in my assay, such as the capture or detection antibody?
Surmodics Assay Diluent is designed for dilution of patient samples that may contain heterophilic antibodies, rheumatoid factors, and other matrix interferences. We do not recommend the dilution of capture antibodies in this diluent. Dilution of detection antibodies with Surmodics Assay Diluent has not been tested, but could be possible in competitive ELISAs and when in search of a completely synthetic diluent.

Does Surmodics Assay Diluent contain Bovine Serum Albumin (BSA)?
No.  Surmodics Assay Diluent is completely protein free and is a proprietary synthetic formulation that completely removes any risk of BSA-related assay or sample interference.
What does Product Code COAT contain?
Product Code COAT is a physiological saline solution containing a proprietary blend of monobasic and dibasic phosphates.

What are the benefits of using Product Code COAT?
Product Code COAT maximizes specific binding to the target solid phase by providing optimal pH and ionic strength for antigen or antibody binding.

Can Product Code PBSC be used with other phosphate groups?
Product Code PBSC should not be used in assays where there is a competition for phosphate groups, if complex formulations with metal ions are essential for the enzyme activation.

What will the phosphate ions in Product Code PBSC inhibit?

Phosphate ions will inhibit carboxypeptidase, carboxylase, urease, muscle deaminase, formase, and phosphoglucomutase.