LoDLoQVerificationChecker

URS & FS — User Requirements and Functional Specification

This document describes the controlled interface and behaviour of LoDLoQVerificationChecker for LoD/LoQ Verification Checker.

Domain limits and critical parameters

• LoD/LoQ Verification Checker — Independent Verification of Detection and Quantitation Limits
• ℹ️ Utility performs statistical verification of declared LoD and LoQ according to CLSI EP17-A3, FDA Bioanalytical Method Validation Guidance and ICH Q2(R2):
• • Detection Rate: Observed detection frequency at declared LoD must be ≥ target (typically ≥95%).
• • Binomial 95% CI: Lower confidence bound must exceed minimum acceptable rate.
• • Test Concentration: Testing MUST be performed AT declared LoD concentration (±10% tolerance).
• • Minimum Measurements: ≥20 total measurements for statistical power.
• • Precision (CV%): Observed CV at LoQ ≤ target threshold (typically ≤20%).
• • Accuracy (Bias%): Observed bias at LoQ ≤ target threshold (typically ≤±20%).
• • Replicates: ≥20 replicates for reliable precision estimation.
• • Verification ≠ establishment. Verification tests ONE concentration (declared limit).
• • Detection rate <95% does NOT necessarily mean true LoD is higher — may need more measurements.
• • Binomial CI is critical: 19/20 = 95%, but 95% CI = [75.1%-99.9%]. Lower bound <90%!
• • LoQ without BOTH CV AND bias confirmation = unverified limit.
• • Test concentration must match declared limit (±10%). Otherwise verification is invalid.
• ⚠️ CRITICAL:
• • LoD Detection Rate ≥ Min Acceptable (typically ≥90%)
• • LoD Binomial CI Lower Bound ≥ Min Rate
• • LoQ CV ≤ Max% | LoQ |Bias| ≤ Max%

URS — User Requirements Specification

input.csv contract

AssayName,Analyte,VerificationContext,DeclaredLoD,DeclaredLoQ,Units,LoD_NumSamples,LoD_NumReplicates,LoD_TestConcentration,LoD_DetectedCount,LoD_TargetDetectionRate,LoD_MinAcceptableDetectionRate,LoQ_NumReplicates,LoQ_TestConcentration,LoQ_ObservedCV_Percent,LoQ_MaxCV_Percent,LoQ_ObservedBias_Percent,LoQ_MaxBias_Percent,LoQ_TrueValue,ConfidenceLevel
OncoLiquid_cfDNA,EGFR_L858R,Reagent_Change,0.005,0.01,% VAF,5,6,0.005,29,0.95,0.90,25,0.01,14.2,20.0,6.5,20.0,0.01,0.95
MRD_Panel_v3,TP53_ctDNA,Method_Transfer,0.001,0.003,% VAF,4,5,0.001,15,0.95,0.90,20,0.003,28.5,20.0,18.0,20.0,0.003,0.95

Input validation rules

FS — Functional Specification

Example output.json

{
  "utilityId": "lodloqverificationchecker",
  "utilityFolder": "LoDLoQVerificationChecker",
  "package": "LiquidBiopsy",
  "overallStatus": "PASS|WARNING|FAIL",
  "sourceFile": "input.csv",
  "processedAtUtc": "2026-06-10T00:00:00Z",
  "checks": [
    {
      "parameter": "AssayName",
      "value": "OncoLiquid_cfDNA",
      "status": "PASS|WARNING|FAIL",
      "message": "Deterministic rule-based check result",
      "ruleReference": "FS-RULE-001"
    },
    {
      "parameter": "Analyte",
      "value": "EGFR_L858R",
      "status": "PASS|WARNING|FAIL",
      "message": "Deterministic rule-based check result",
      "ruleReference": "FS-RULE-002"
    },
    {
      "parameter": "VerificationContext",
      "value": "Reagent_Change",
      "status": "PASS|WARNING|FAIL",
      "message": "Deterministic rule-based check result",
      "ruleReference": "FS-RULE-003"
    },
    {
      "parameter": "DeclaredLoD",
      "value": "0.005",
      "status": "PASS|WARNING|FAIL",
      "message": "Deterministic rule-based check result",
      "ruleReference": "FS-RULE-004"
    },
    {
      "parameter": "DeclaredLoQ",
      "value": "0.01",
      "status": "PASS|WARNING|FAIL",
      "message": "Deterministic rule-based check result",
      "ruleReference": "FS-RULE-005"
    },
    {
      "parameter": "Units",
      "value": "% VAF",
      "status": "PASS|WARNING|FAIL",
      "message": "Deterministic rule-based check result",
      "ruleReference": "FS-RULE-006"
    },
    {
      "parameter": "LoD_NumSamples",
      "value": "5",
      "status": "PASS|WARNING|FAIL",
      "message": "Deterministic rule-based check result",
      "ruleReference": "FS-RULE-007"
    },
    {
      "parameter": "LoD_NumReplicates",
      "value": "6",
      "status": "PASS|WARNING|FAIL",
      "message": "Deterministic rule-based check result",
      "ruleReference": "FS-RULE-008"
    },
    {
      "parameter": "LoD_TestConcentration",
      "value": "0.005",
      "status": "PASS|WARNING|FAIL",
      "message": "Deterministic rule-based check result",
      "ruleReference": "FS-RULE-009"
    },
    {
      "parameter": "LoD_DetectedCount",
      "value": "29",
      "status": "PASS|WARNING|FAIL",
      "message": "Deterministic rule-based check result",
      "ruleReference": "FS-RULE-010"
    },
    {
      "parameter": "LoD_TargetDetectionRate",
      "value": "0.95",
      "status": "PASS|WARNING|FAIL",
      "message": "Deterministic rule-based check result",
      "ruleReference": "FS-RULE-011"
    },
    {
      "parameter": "LoD_MinAcceptableDetectionRate",
      "value": "0.90",
      "status": "PASS|WARNING|FAIL",
      "message": "Deterministic rule-based check result",
      "ruleReference": "FS-RULE-012"
    }
  ],
  "criticalFindings": [],
  "warnings": [],
  "audit": {
    "inputHash": "sha256:<calculated at runtime>",
    "rulesVersion": "<utility executable version>",
    "documentation": "LoDLoQVerificationChecker.documentation.html"
  }
}

Traceability matrix

IQ/OQ/PQ test scenarios

QA/QC and change control

• Do not rename columns without updating validator, documentation and test set.
• Retain input.csv, output.json, executable version and checksum.
• Before production use, perform IQ/OQ/PQ or equivalent CSV/CSA verification.
• Critical limits shall be verified against the approved specification, registration dossier and local SOPs.
• The utility provides structured QC decision support; final release decision remains with QA/QP and approved procedures.