Method Validation Calculator
1

Assay Type

Acceptance Criteria ?
Min R² (linearity)
Max y-int Bias (%)
Recovery Min (%)
Recovery Max (%)
Repeat. %RSD Max
Intermed. %RSD Max
2

Calibration Standards

Response Units ?
Conc.Response
4

Accuracy (% Recovery)

Enter known vs. found concentrations ?
KnownFound
4

Precision (Repeatability)

Replicate measurements ?
Rep #Result
4

Intermediate Precision

All results across days/analysts ?
Day/RunResult
3

Linearity Assessment

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R²
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Slope
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Intercept
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y-int Bias %
3

Residual Plot

3

Detection & Quantitation Limits

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LOD
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LOQ
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Residual SD (σ)
4

Accuracy & Precision Results

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Mean Recovery %
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Repeat. %RSD
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Intermed. %RSD
5

Validation Summary (ICH Q2)

About Analytical Method Validation (ICH Q2)

Analytical method validation confirms that an analytical procedure is suitable for its intended purpose. ICH Q2(R2), finalized in 2023, defines the core validation characteristics: specificity, linearity, range, accuracy, precision (repeatability and intermediate precision), limit of detection (LOD), and limit of quantitation (LOQ). This method validation calculator automates the most commonly calculated parameters from calibration curve data and replicate measurements, providing instant pass/fail assessment against user-defined acceptance criteria aligned with ICH Q2(R2) and industry consensus thresholds for each assay type.

The Limit of Detection is calculated as LOD = 3.3 × σ / S and the Limit of Quantitation as LOQ = 10 × σ / S, where σ is the residual standard deviation from the calibration curve linear regression and S is the slope. Linearity is assessed by the coefficient of determination (R²), residual plot analysis for systematic patterns, and y-intercept bias relative to the 100% target level response. Accuracy is reported as percent recovery from spiked or reference samples, and precision is expressed as percent relative standard deviation (%RSD) from replicate measurements.

ICH Q14, adopted alongside Q2(R2) in 2023, introduces lifecycle management of analytical procedures through the Analytical Target Profile (ATP) and Method Operable Design Region (MODR). Together, Q2(R2) and Q14 modernize analytical validation from a one-time event to an ongoing, science-based, risk-managed approach. Every QC laboratory in pharmaceutical, biopharmaceutical, food safety, environmental, and clinical chemistry settings performs method validation. This calculator supports the most common bioprocess assay types: SEC-HPLC, CE-SDS, ELISA, qPCR, BCA/Bradford, direct A280, LAL endotoxin, and icIEF.

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Frequently Asked Questions

How do you calculate LOD and LOQ from a calibration curve?

LOD = 3.3 × σ / S and LOQ = 10 × σ / S, where σ is the residual standard deviation from the calibration curve regression and S is the slope. This is the ICH Q2(R2) calibration curve method. Alternative approaches use the SD of blank responses or y-intercepts from multiple curves.

What R² value is acceptable for linearity?

ICH Q2(R2) does not mandate a universal R² cutoff, but industry consensus is R² ≥ 0.990 for most bioanalytical methods, ≥ 0.998 for chromatographic assays (HPLC), and ≥ 0.990 for immunoassays (ELISA). Always examine residual plots for patterns, not just R².

What is the difference between repeatability and intermediate precision?

Repeatability measures variation under identical conditions (same analyst, instrument, day) with 6+ replicates. Intermediate precision captures day-to-day, analyst-to-analyst, or instrument-to-instrument variation. Both are reported as %RSD. Typical targets: repeatability ≤ 2% for HPLC, ≤ 5% for ELISA; intermediate precision ≤ 5% for HPLC, ≤ 10% for ELISA.

How do you assess accuracy in method validation?

Accuracy is assessed at 3+ concentration levels (typically 80%, 100%, 120% of target) with 3 replicates each. Report mean % recovery = (found / known) × 100. Acceptance varies by method: 98-102% for HPLC, 95-105% for general methods, 80-120% for immunoassays.

What changed in ICH Q2(R2) vs the original ICH Q2?

ICH Q2(R2) (2023) adds biological/biotechnological product scope, multivariate procedure guidance (NIR, Raman), real-time testing, and alignment with ICH Q14 lifecycle management through Analytical Target Profiles (ATP). The core validation characteristics are unchanged.

What is ICH Q14 and the Method Operable Design Region (MODR)?

ICH Q14 introduces lifecycle management for analytical procedures. The MODR defines proven acceptable ranges for method parameters (analogous to the design space in ICH Q8). Changes within the MODR do not require prior regulatory approval, reducing post-approval supplements.