Quantikine ELISA Validation: Making the Industry Gold Standard

Thursday, June 22, 2017 - 13:28
Quantikine ELISA Kit Validation

When selecting an ELISA kit, different users often have different criteria in making their choice, whether it is sensitivity, sample types, or ease-of-use. One universal criterion is that an ELISA must work the first time and every time you use it. R&D Systems has developed our
Quantikine® ELISAs from raw materials that we make in-house, giving us unparalleled control over critical elements that affect your results and creating consistency of results over long periods of time. Whether you are breaking new ground or building on the work of others, you can trust that the results will be reproducible tomorrow, next week, and next year. Read below to see how we do it.

It Starts with Development

Manufacturing a quality ELISA kit begins with the reagents and optimization that takes place during the development of the assay. Antibodies and diluents are developed and tested in-house, and carefully selected to meet high performance criteria, stringent manufacturing guidelines, and quality control standards. Rigorous development and validation testing guarantees the ELISA will perform with the ultimate precision, specificity, accuracy, and sensitivity.

Confirmed Lot-to-Lot Consistency

All lots are tested to ensure low background, a linear standard curve, consistent assay sensitivity, and a broad dynamic standard curve range. A master calibrated standard is built during development, calibrated against highly purified material, and is used to build and qualify all future lots of standard. This guarantees that your sample values will not shift or change over time. Consistent control values established during assay development and validation ensure that sample data is comparable over time.

Quantitation of Human IL-6 in High, Medium, and Low Controls
Quantitation of Human IL-6 in High, Medium, and Low Controls. High (blue line), medium (red line), and low (green line) controls are assayed with every manufactured lot of the Human IL-6 Quantikine® ELISA Kit (Catalog # D6050). Controls for the Human IL-6 Quantikine® ELISA Kit fall within acceptable ranges (gray bars) and remain consistent from lot to lot.

Precise Quantitation of the Target Analyte

Assay diluents are carefully optimized for each Quantikine® ELISA Kit in order to minimize assay interference due to nonspecific binding, antibody interference, and cross-reactivity, which can be caused by assay surfaces or endogenous substances present in biological samples. Spike recovery and assay linearity experiments ensure that data are accurate for all validated sample types.

Assay Linearity as a Measure of Immunoassay Accuracy
Assay Linearity as a Measure of Immunoassay Accuracy. Heparin plasma samples spiked with recombinant human Thrombomodulin were serially diluted. Thrombomodulin was quantitated using the Human Thrombomodulin/BDCA-3 Quantikine® ELISA Kit (Catalog # DTHBD0; green line) or an ELISA from a competitor (red line). Assay linearity values for the Quantikine® ELISA kit fell within acceptable values (90–110% of the undiluted samples), while samples measured using a competitor’s ELISA did not (141–325% of the undiluted samples).

Accurate Detection of Natural Proteins

Antibody pairs recognize the supplied recombinant standard and the natural proteins in biological samples in a parallel manner, confirming that Quantikine® ELISA Kits can be used to measure the relative mass values of the natural analyte. Protein standards are correlated to the NIBSC/WHO standard when available. R&D Systems has determined the ideal standard curve range for each assay, ensuring peak sensitivity and reproducibility of results.

Recognition of Recombinant and Natural Human TGF-beta 1
Recognition of Recombinant and Natural Human TGF-beta 1. Serial dilutions of rhTGF-beta 1 standard (red line) or natural TGF-beta 1 present in serum (green line) were quantitated using the Human TGF-beta 1 Quantikine® ELISA Kit (Catalog # DB100B). Quantikine® ELISAs detect both recombinant and natural proteins in a parallel manner across a range of concentrations.

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