Technetium99mRedBloodCellChecker

URS & FS — User Requirements and Functional Specification

This document describes the controlled interface and behaviour of Technetium99mRedBloodCellChecker for Tc-99m RBC.

Domain limits and critical parameters

• ℹ️ Utility checks critical parameters of Tc-99m RBC:
• • Labeling efficiency (≥95%)
• • Free pertechnetate (≤3%)
• • Colloidal technetium (≤2%)
• • pH (4.5–7.5), endotoxins, sterility
• ⚠️ CRITICAL: Low labeling (<95%) leads to stomach accumulation.
• BatchNumber,TotalActivityMBq,LabelingEfficiencyPercent,FreePertechnetatePercent,ReducedHydrolyzedTcPercent,pH,EndotoxinsEU,SterilityTest,HematocritPercent,LabelingMethod
• Example (sterility: 0=sterile, 1=contaminated):
• ⚠️ CRITICAL:
• • Labeling Efficiency ≥95% — The most important characteristic. If technetium is not bound to the RBC, it behaves like free pertechnetate or colloid.
• • Free pertechnetate ≤3% — Enters stomach and thyroid. When searching for GI bleeding, stomach uptake can be mistaken for bleeding or obscure it. In cardiology, stomach background interferes with inferior wall assessment.
• • Reduced/Hydrolyzed Tc ≤2% — Accumulates in liver and spleen. Interferes with hemangioma visualization and creates background for the heart.
• • Endotoxins ≤175 EU/vial, Sterility — standard requirements for IV injections.
• • Assessment of free technetium impact on specific studies (GI/Heart)

URS — User Requirements Specification

input.csv contract

BatchNumber,TotalActivityMBq,LabelingEfficiencyPercent,FreePertechnetatePercent,ReducedHydrolyzedTcPercent,pH,EndotoxinsEU,SterilityTest,HematocritPercent,LabelingMethod
TC99M-RBC-2026-100,925.0,98.0,1.5,0.5,7.4,10.0,0,45.0,InVivo
TC99M-RBC-FAIL-101,900.0,85.0,12.0,3.0,7.2,15.0,0,42.0,InVivo
TC99M-RBC-VITRO-102,740.0,99.5,0.5,0.0,7.5,5.0,0,40.0,InVitro

FS — Functional Specification

Example output.json

{
  "utilityId": "technetium99m-red-blood-cell-checker",
  "api": "Tc-99m RBC",
  "overallStatus": "PASS|WARNING|FAIL",
  "sourceFile": "input.csv",
  "checks": [
    {
      "parameter": "BatchNumber",
      "value": "TC99M-RBC-2026-100",
      "status": "PASS|WARNING|FAIL",
      "message": "Rule-based check result"
    },
    {
      "parameter": "TotalActivityMBq",
      "value": "925.0",
      "status": "PASS|WARNING|FAIL",
      "message": "Rule-based check result"
    },
    {
      "parameter": "LabelingEfficiencyPercent",
      "value": "98.0",
      "status": "PASS|WARNING|FAIL",
      "message": "Rule-based check result"
    },
    {
      "parameter": "FreePertechnetatePercent",
      "value": "1.5",
      "status": "PASS|WARNING|FAIL",
      "message": "Rule-based check result"
    },
    {
      "parameter": "ReducedHydrolyzedTcPercent",
      "value": "0.5",
      "status": "PASS|WARNING|FAIL",
      "message": "Rule-based check result"
    },
    {
      "parameter": "pH",
      "value": "7.4",
      "status": "PASS|WARNING|FAIL",
      "message": "Rule-based check result"
    },
    {
      "parameter": "EndotoxinsEU",
      "value": "10.0",
      "status": "PASS|WARNING|FAIL",
      "message": "Rule-based check result"
    },
    {
      "parameter": "SterilityTest",
      "value": "0",
      "status": "PASS|WARNING|FAIL",
      "message": "Rule-based check result"
    }
  ],
  "criticalFindings": []
}

OQ/PQ test scenarios

QA/QC and change control

• Do not rename columns without updating the validator 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 radiopharmaceutical limits must be verified against the approved specification and local SOPs.