Labreador v1.5 is the biggest release since launch. The headline is a brand-new Parallel Line Analysis (PLA) module for relative potency — the same statistical machinery regulators expect for biological batch release — but the update also brings sharper diagnostics, cleaner exports, and a handful of fixes that make everyday work faster. Everything still runs in your browser; no data ever leaves the device.

New: Parallel Line Analysis module

A dedicated workspace for comparing a test sample against a reference standard and reporting relative potency (RP %) — the metric required by Ph. Eur. 5.3 and USP <1032/1034> for biological products.

Joint 4PL / 5PL fit under both the parallel (shared A, B, D) and non-parallel model.
F-test for parallelism — the pass/fail gate that decides whether an RP number is defensible at all.
Relative potency with two CIs side by side: analytical Fieller's 95 % CI and a residual bootstrap 95 % CI (500 iterations), so you can cross-check.
Quality gate aggregating parallelism, R², CI width, concentration overlap, and variance homogeneity into a single PASS / WARN / FAIL verdict.
CSV + high-resolution PNG export for reports.

New: Combine multiple assay runs

Toggle at the top of the PLA page. Enter 3 – 6 independent runs (each with its own reference/test data, model, and weighting) and get a single combined potency.

Weighted geometric mean of RP across runs, with inverse-variance weights derived from each run's CI.
χ² homogeneity test (Ph. Eur. 5.3 §6) that tells you whether the runs actually agree before you report the combined value.
Runs with undefined CI are automatically excluded from the pool and flagged in the per-run table.

Sharper diagnostics

Fit parameters table — reference vs test side by side (A, B, C, D, [G], R², n). Makes it obvious when a shared parameter is drifting even though the F-test passes.
Residual plot (collapsible) — predicted vs residual with ±2σ guides and an auto-generated interpretation caption ("no systematic pattern" vs "curved residuals — consider 5PL").
Smart suggestions banner — flags EC50 near the edge of the tested range, poor concentration overlap, and cases where 5PL would likely fit better than 4PL.
Interactive outlier exclusion on the curve chart — click a point to drop it, click again to bring it back. Grubbs ESD pre-flags candidates.
Lack-of-fit F-test (when replicates exist) that separates pure error from model misfit.
Levene / Brown-Forsythe test for variance homogeneity between reference and test, feeding directly into the quality gate.

Regression weighting

A segmented control next to the model toggle: None, 1/y, 1/y². Applies consistently to the fit, the F-test, and the bootstrap — so switching to 1/y² when the assay CV is roughly constant across the dose range does not silently break the CI.

Fixes and polish

Scatter dots on the PLA curve chart now sit on the curves instead of stacking at the top of the plot.
Interactive-mode disclaimer in the PLA chart is now a small collapsible hint and is excluded from PNG exports, so screenshots stay clean.
In-app guide for PLA rewritten with worked examples, failure modes, and regulatory references.

Documentation and standards

PLA is fully documented in the in-app guide (top-right of the module). The maths follows Ph. Eur. 5.3 — including §6 for combining runs — and USP <1032/1034> for the acceptance framework. As always, Labreador is a research and method-development tool, not a GMP release instrument; but the calculations are the same calculations regulators check.

Cite this version

If you cite Labreador in a methods section, please update to the v1.5 record:

Labreador — Bioassay Analysis Platform (Version 1.5.0) [Computer software]. Zenodo. https://doi.org/10.5281/zenodo.21336603

Feedback and bug reports are welcome — the PLA module in particular benefits from real-world datasets, so send them our way.