Labreador — Bioassay Analysis Platform Blog
Methodology notes, step-by-step guides, and release notes for scientific bioassay analysis.
How to Calculate Estimated Daily Intake (EDI) for Heavy Metals in Food
Step-by-step guide to estimated daily intake of trace elements from food: the EDI formula, ingestion rates, body weight defaults, worked example, and how EDI feeds into THQ and Hazard Index.
How to Calculate Percent Inhibition from Plate Reader Data Before Fitting IC50
Calculate percent inhibition with control-based formulas, a worked Excel example, and a Labreador workflow that avoids confusing activity with inhibition.
How to Fit a 4PL ELISA Standard Curve in Excel (and a Faster Free Alternative)
Step-by-step: fit a 4PL ELISA standard curve in Excel with Solver, interpolate sample concentrations, and see why a free browser tool does the same in two minutes.
How to Prepare an ELISA Standard Curve: Serial Dilution Step by Step
How to prepare ELISA standards: choosing the top concentration, dilution factor and volumes, a worked 2-fold serial dilution, pipetting tips and common mistakes.
How to Choose Concentrations for an IC50 Dose-Response Experiment
Practical guide to designing a dose-response experiment: concentration range, number of points, dilution factor, replicates, controls and plate layout for a reliable IC50.
BCA vs Bradford Protein Assay: Which One Should You Use?
BCA vs Bradford compared: chemistry, working range, interfering substances, standard curve fitting and how to use protein results to normalize ELISA data.
ANOVA or Kruskal-Wallis? How to Compare Three or More Groups
A practical guide to choosing between one-way ANOVA and the Kruskal-Wallis test when you have three or more groups, plus post-hoc corrections and reporting rules.
t-test or Mann-Whitney? How to Choose the Right Test for Two Groups
A practical decision guide for comparing two groups in lab data: when a t-test is valid, when Mann-Whitney is safer, what normality tests really tell you, and how to report results correctly.
The Hook Effect in ELISA: When More Analyte Gives You a Lower Signal
Why very concentrated samples can read falsely low in sandwich ELISA — how the hook (prozone) effect works, how to detect it with dilution series, and how to report it correctly.
Target Hazard Quotient (THQ) Explained: Assessing Health Risk from Heavy Metals in Food
What the target hazard quotient is, how to calculate EDI, THQ and the hazard index (HI) for heavy metals in fish and food, and how to interpret the results — with worked examples.
ELISA Troubleshooting Guide: Weak Signal, High Background, High CV and Other Common Problems
A practical troubleshooting guide for the most common ELISA failures — weak signal, high background, high CV between replicates, edge effects and bad standard curves — with causes and fixes.
Spike Recovery and Dilution Linearity in ELISA: How to Prove Your Matrix Is Not Lying
Practical protocols and acceptance criteria for ELISA spike recovery, dilution linearity and parallelism — how to detect matrix effects, the hook effect and the correct minimum required dilution.
How to Calculate Km and Vmax: A Practical Enzyme Kinetics Guide
Step-by-step guide to Michaelis-Menten kinetics: measuring initial rates, fitting Km and Vmax, why Lineweaver-Burk plots mislead, and how to report results correctly.
4PL vs 5PL for ELISA Standard Curves: Why Log-Linear Regression Fails
ELISA standard curves are sigmoidal, not straight. Learn why four-parameter logistic (4PL) and five-parameter logistic (5PL) fitting outperforms linear or log-linear regression, and when to use each model.
How to Calculate LOD and LOQ: Formulas, Methods and Common Mistakes
Three accepted ways to calculate the limit of detection (LOD) and limit of quantitation (LOQ) — blank SD, calibration-curve residuals, and the S/N approach — with formulas, worked numbers and reporting rules.
BCF, BAF and BSAF: How to Calculate Bioaccumulation Factors Correctly
A practical guide to bioconcentration (BCF), bioaccumulation (BAF) and biota-sediment accumulation (BSAF) factors — formulas, units, dry vs wet weight, non-detects, and how to interpret the thresholds.
ELISA Data Analysis: A Step-by-Step Guide (2026)
How to analyze ELISA data end to end: blank subtraction, 4PL/5PL standard curve fitting, sample interpolation, LLOQ/ULOQ limits, %CV and recovery checks.
Local-First Science: Why Your Assay Data Should Never Leave the Browser
In 2026, cloud-hosted lab tools are quietly training on your raw data. Here is why local-first, zero-data-storage scientific software is becoming the new default — and how Labreador implements it.
Beyond R²: What to Actually Check for ELISA Method Quality
A practical checklist of the metrics that decide whether an ELISA run is trustworthy — dynamic range, S/B, EC50 placement, CI width, recovery — and how Labreador's Method Health Panel surfaces them automatically.
Labreador v1.5 — Parallel Line Analysis, Combined Assays, and Smarter Diagnostics
What is new in Labreador v1.5: a full Parallel Line Analysis module with relative potency, multi-run combination, Fieller CI, weighted regression, and quality-of-life polish across the app.
Parallel Line Analysis: The One Test That Separates Biosimilars From Bench Curiosities
Why pharmacopoeias require Parallel Line Analysis for every batch of a biological product, how relative potency is actually computed, and the failure modes that quietly invalidate it.
Z'-Factor: The One Number That Tells You If Your Assay Is Worth Running
How the Z'-factor separates publishable assays from noise, why 0.5 is the magic threshold, and how to calculate it correctly for ELISA, dose-response, and HTS screens.
IC50 vs EC50: What They Mean, How to Calculate Them, and When Each Applies
Clear, practical guide to IC50 and EC50: definitions, when to use which, how they're calculated from a dose-response curve, and common pitfalls in fitting and reporting.
R² Is Not Enough: A 3-Tier Quality Gate for ELISA Curves
Why a single R² value misleads on heteroscedastic ELISA curves, and how a 3-tier acceptance gate (≥0.98 / 0.95–0.98 / <0.95) protects sample interpolation.
Understanding Pollution Indices: CF, PLI and MPI Explained
A practical guide to Contamination Factor, Pollution Load Index and Metal Pollution Index — what they measure, how they are calculated, and how to interpret them in environmental studies.
Welcome to the Labreador Blog
An introduction to the Labreador blog — practical guides on bioassay analysis, methodology notes, and tutorials for ELISA, dose-response, kinetic, and ecotoxicology workflows.