Question: Can General Assay Diluent be used as sample/standard diluent?
Answer: Our General Assay Diluent can be used as sample/standard diluent, however the matrix is more complex than is found in a typical sample diluent, so depending on the assay you may find that it reduces signal/sensitivity. If this occurs, it can generally be addressed with other adjustments to the assay, such as increased incubation times and/or antibody concentrations.
Our sample diluents and assay diluents serve similar functions. Generally speaking, we look at our sample diluents as the investigators’ first method of diluting the samples to read within the functional range of the assay. Sample diluents contain additives to support antigen-antibody binding interactions, minimize matrix effects, reduce non-specific binding, etc. Often customers developing an assay try to optimize first with a sample diluent. Generally speaking, if you can get by with diluting your serum samples at least 1:4 or 1:5, matrix effect will not be an issue. In some assays, additional complex issues may require additional support beyond the help provided by the sample diluent. For example, situations where serum samples cannot be diluted very much because the target analyte is found at too low of a concentration.
We look at our assay diluents as a second level of support to address these more complex assay issues. To use, the assay diluent is normally put into every well (including BOTH samples and standards) across the entire ELISA plate (we recommend 50 µL/well) BEFORE adding standards and samples. Our assay diluents help equalize differences between calibrator and sample matrices in order to establish a useful standard curve. They also address other unique issues. For example, in situations where IgM-mediated conjugate bridging is contributing to substantial background noise, IgM-Reducing Assay Diluent is recommended.
All our assay diluents contain additives to inhibit clotting in plasma and serum samples, while of our sample diluent offerings, only Plasma Sample Diluent has been formulated for this.
If you have questions you would like answered, please contact us here or give us a call at (800) 824-8540. We love to hear from you!