Biomarkers are central to diagnosing and managing patients in clinical medicine. ELISA assays are frequently used to measure biomarkers in clinical samples. However, the ELISA method differs in quality and may introduce systematic and random errors. Hence, clinical analysis requires more rigorous assay performance. ELISA assay validation demonstrates the suitability of an ELISA assay to meet its intended application.
Whether it’s an ELISA assay or an HPLC test, ELISA assay development and validation are critical for demonstrating the reliability of an ELISA assay. A thorough assay development and ELISA validation approach will ensure reliable, reproducible, and accurate results. ELISA labs should consider multiple regulatory requirements while validating ELISA methods. Hence, the current article discusses regulatory considerations for ELISA assay validation in clinical use.
ELISA assay validation in clinical research
Often, clinical biomarkers are present in low abundance and require ELISA assays with enough sensitivity. However, rigorous assay performance is crucial for reproducible and reliable results. Researchers perform assay validation by examining and providing evidence that a particular ELISA method is specific for its intended applications. Here, the intended use of an ELISA assay needs to be specified before beginning with method validation experiments. The intended application of ELISA assays will depend on the research question. For example, ELISA assays are used in study outcomes as a diagnostic marker.
Different analytical techniques have unique validation requirements. For example, chromatography-based approaches require carry-over assessments, while they are not applicable for ELISA analysis. Hence, identifying a bioanalytical method is as crucial as evaluating the analyte of interest.
Today, researchers employ a fit-for-purpose approach in ELISA assay validation. This approach states that the extent of method validation depends on the intended use of an ELISA assay. Hence, the extent of ELISA assay validation will depend on the analyte of interest and the stage at which the method is developed in drug development. Exploratory studies will require a partial method validation. However, clinical studies require a full method validation.
Moreover, full and partial method validation has unique requirements. For example, an ELISA assay developed in-house requires full method validation. On the other hand, a commercial ELISA assay will need a partial method validation of parameters except for robustness. Hence, partial method validation may range from assessing assay sensitivity to nearly a full method validation.
A validation report is a critical component of assay validation documentation. Laboratories should record all the results obtained during ELISA assay validation to comply with ISO standards. Hence, robust validation reports are critical.
ELISA assay validation includes evaluating different assay parameters such as robustness, precision, trueness, uncertainty, limits of quantification, dilution linearity, parallelism, recovery, selectivity, and sample stability. Each of these parameters is unique for a bioanalytical assay. Moreover, validation experiments are conducted generally within a month. Hence, an internal quality control program is required to ensure that the assay quality does not diminish over time.
In conclusion
ELISA immunoassays are the gold standard for evaluating analytes in complex biological samples. However, a complete and robust ELISA assay validation is crucial for generating reliable experimental data.
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