Free Bioanalytical Tools for ELISA Development
FDA Bioanalytical Guidance (2018) ligand-binding-assay validation calculators — accuracy & precision, LLOQ, dilutional linearity, selectivity, specificity, and prozone/hook-effect checks, each built on the same shared 4PL curve engine. Everything runs in your browser. More sections beyond Accuracy & Precision are coming, using the same pattern.
Accuracy & Precision (LBA)
Fit your standard curve, enter QC replicate data across runs at LLOQ/Low/Mid/High/ULOQ, and get FDA Bioanalytical Guidance (2018) Table 1 accuracy, precision, Total Error, and run-acceptance verdicts for ligand-binding assays.
Dilutional Linearity
Fit your standard curve, then paste replicate OD readings for a high-concentration sample diluted across several factors, and get FDA Bioanalytical Guidance (2018) Table 1 dilutional-linearity verdicts for ligand-binding assays — %recovery within 80–120% of expected and ≤20% CV at each dilution factor.
LLOQ (Lower Limit of Quantitation)
Fit your standard curve, enter replicate data at the proposed LLOQ concentration across runs, and get FDA Bioanalytical Guidance (2018) Table 1 sensitivity verdicts for ligand-binding assays — every replicate must pass ±25% of nominal, ±25% CV, and ≤40% Total Error for the LLOQ to be confirmed.
Prozone (Hook Effect)
Enter mean signal readings across a concentration series spanning well above the ULOQ (e.g. 10×, 100×, 1000×), and check for the prozone (hook) effect — FDA Bioanalytical Guidance (2018) requires demonstrating that increasing analyte concentration does not result in decreased signal at the high end of the range.
Selectivity
Fit your standard curve, then paste OD readings from at least 10 individual matrix sources spiked at LLOQ and at a high QC concentration, and get FDA Bioanalytical Guidance (2018) Table 1 selectivity verdicts for ligand-binding assays — each source within ±25% of nominal at LLOQ and ±20% of nominal at the high QC level.
Specificity
Fit your standard curve, then compare a clean reference sample against samples spiked with potential interfering substances, to get FDA Bioanalytical Guidance (2018) Table 1 specificity verdicts for ligand-binding assays — each interferent within ±20% of the reference (±25% if tested at the LLOQ/ULOQ level).