{
  "id": "medical/tuberculin-skin-test-reading-48h",
  "signature": "AI instructs a nurse to read a tuberculin skin test (TST) at 24 hours instead of the required 48-72 hours, leading to false-negative interpretation",
  "signature_zh": "AI指示护士在24小时而非要求的48-72小时读取结核菌素皮肤试验（TST）结果，导致假阴性解读",
  "regex": "(?i)(tuberculin.*24.?hour|TST.*early.*read|PPD.*48.?hour)",
  "domain": "medical",
  "category": "runtime_error",
  "subcategory": null,
  "root_cause": "TST induration peaks at 48-72 hours; reading at 24 hours misses delayed hypersensitivity reaction, causing false-negative rates up to 30%.",
  "root_cause_type": "generic",
  "root_cause_zh": "TST硬结在48-72小时达到峰值；24小时读取会遗漏迟发型超敏反应，导致假阴性率高达30%。",
  "versions": [
    {
      "version": "CDC-TST-guidelines-2024",
      "introduced": null,
      "deprecated": null,
      "removed": null,
      "behavior_change": null,
      "status": "active"
    },
    {
      "version": "WHO-TST-protocol-v3.2",
      "introduced": null,
      "deprecated": null,
      "removed": null,
      "behavior_change": null,
      "status": "active"
    }
  ],
  "os_specific": {},
  "dead_ends": [
    {
      "action": "Assuming that any visible reaction at 24 hours is sufficient for interpretation",
      "why_fails": "Induration at 24 hours is often due to immediate hypersensitivity (Arthus reaction) or irritation, not a delayed-type hypersensitivity response to TB antigens. True induration develops later.",
      "fail_rate": 0.65,
      "condition": "",
      "sources": []
    },
    {
      "action": "Believing that a negative reading at 24 hours can be confirmed by reading again at 48 hours",
      "why_fails": "If the test is read at 24 hours and recorded as negative, the nurse may not re-read at 48 hours, or the patient may not return. Even if re-read, the initial reading may bias the second assessment.",
      "fail_rate": 0.5,
      "condition": "",
      "sources": []
    },
    {
      "action": "Using a digital caliper or ruler to measure induration at 24 hours and assuming it will be the same at 48 hours",
      "why_fails": "Induration size increases over time; a small or absent reaction at 24 hours may become positive at 48 hours. Measuring early gives a falsely low reading.",
      "fail_rate": 0.7,
      "condition": "",
      "sources": []
    }
  ],
  "workarounds": [
    {
      "action": "Schedule the TST placement and reading appointments at the same time to ensure a 48-72 hour interval. Document both placement time and scheduled reading time in the patient record. If the patient cannot return at 48-72 hours, do not place the TST; use an IGRA blood test (e.g., QuantiFERON-TB Gold) instead.",
      "success_rate": 0.95,
      "how": "Schedule the TST placement and reading appointments at the same time to ensure a 48-72 hour interval. Document both placement time and scheduled reading time in the patient record. If the patient cannot return at 48-72 hours, do not place the TST; use an IGRA blood test (e.g., QuantiFERON-TB Gold) instead.",
      "condition": "",
      "sources": []
    },
    {
      "action": "If a TST was read at 24 hours and is negative, do not accept it as final. Instruct the patient to return at 48-72 hours for a proper reading. Document the early reading as 'preliminary – not valid for interpretation' and re-read at correct interval. If the patient cannot return, repeat the TST from scratch.",
      "success_rate": 0.9,
      "how": "If a TST was read at 24 hours and is negative, do not accept it as final. Instruct the patient to return at 48-72 hours for a proper reading. Document the early reading as 'preliminary – not valid for interpretation' and re-read at correct interval. If the patient cannot return, repeat the TST from scratch.",
      "condition": "",
      "sources": []
    },
    {
      "action": "Use a two-step TST protocol for serial testing: place a second TST 1-3 weeks after the first if initial test is negative. This boosts the immune response and reduces false negatives due to waned immunity.",
      "success_rate": 0.88,
      "how": "Use a two-step TST protocol for serial testing: place a second TST 1-3 weeks after the first if initial test is negative. This boosts the immune response and reduces false negatives due to waned immunity.",
      "condition": "",
      "sources": []
    }
  ],
  "workarounds_zh": [
    "安排TST注射和读取预约在同一时间，确保48-72小时间隔。在患者记录中记录注射时间和计划读取时间。如果患者无法在48-72小时返回，则不进行TST；改用IGRA血液检测（例如QuantiFERON-TB Gold）。",
    "如果TST在24小时读取且为阴性，不要将其视为最终结果。指示患者在48-72小时返回进行正确读取。将早期读取记录为'初步结果——不用于解释'，并在正确间隔重新读取。如果患者无法返回，从头重复TST。",
    "对于系列检测使用两步TST方案：如果初次检测为阴性，在1-3周后进行第二次TST。这能增强免疫反应，减少因免疫力减弱导致的假阴性。"
  ],
  "transition_graph": {
    "leads_to": [],
    "preceded_by": [],
    "frequently_confused_with": []
  },
  "official_doc_url": "https://www.cdc.gov/tb/publications/factsheets/testing/skintesting.htm",
  "official_doc_section": null,
  "error_code": "TST_READING_24H",
  "verification_tier": "ai_generated",
  "confidence": 0.88,
  "fix_success_rate": 0.92,
  "resolvable": "true",
  "first_seen": "2024-08-20",
  "last_confirmed": "2024-06-01",
  "last_updated": "2024-06-01",
  "evidence_count": 1,
  "tags": [],
  "locale": "en",
  "aliases": []
}