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  <head>
    <title>064-02 Measurement uncertainty, longitudinal interpretation, imaging choice, and result ownership</title>
    <ownerName>Integrated Medical Foundations</ownerName>
  </head>
  <body>
    <outline text="Measurement uncertainty and result ownership">
      <outline text="Tests as probability interventions">
        <outline text="Value only when result changes care"/>
        <outline text="Harms: false reassurance, false alarms, cost, delay"/>
        <outline text="Before ordering: target, pretest, threshold, action"/>
        <outline text="Sensitivity and specificity tied to population and threshold"/>
        <outline text="Predictive values shift with prevalence">
          <outline text="Low-risk positives mostly false"/>
        </outline>
        <outline text="Published performance may not transport"/>
      </outline>
      <outline text="Thresholds and continuous values">
        <outline text="Testing threshold between treat and exclude">
          <outline text="Neither crossed: repeat, new principle, observe"/>
        </outline>
        <outline text="Harmful false negative lowers exclusion threshold"/>
        <outline text="Invasive treatment harm raises treatment threshold"/>
        <outline text="Values, follow-up, disease speed move thresholds"/>
        <outline text="Continuous values beat binary flags">
          <outline text="Potassium 6.8 is not 5.2"/>
        </outline>
        <outline text="One in twenty healthy results outside range">
          <outline text="Twenty tests make a flag likely"/>
        </outline>
      </outline>
      <outline text="Pre-analytical error and timing">
        <outline text="Occurs before the analyser sees the specimen"/>
        <outline text="Haemolysis releases potassium and enzymes"/>
        <outline text="Underfilled citrate: excess anticoagulant, long clotting"/>
        <outline text="Blood gas changes with air and metabolism"/>
        <outline text="Critical values: assess patient, not auto-dismiss"/>
        <outline text="Sample time recorded relative to treatment"/>
        <outline text="Line sampling: discard volume, stop infusion"/>
        <outline text="Scarce fluids: prioritise tests in advance"/>
      </outline>
      <outline text="Post-analytical error and ownership">
        <outline text="Units, ranges, transcription, inbox routing fail"/>
        <outline text="Unfinished until a named clinician acts">
          <outline text="Electronic delivery alone is not closed loop"/>
        </outline>
        <outline text="Pending results at discharge need owner"/>
        <outline text="Critical call: read back identity, value, time">
          <outline text="Use escalation route if clinician absent"/>
        </outline>
        <outline text="Tell patients: confirmed or preliminary, urgency"/>
        <outline text="Ownership and named alternate prevent misses"/>
      </outline>
      <outline text="Blood count and electrolytes">
        <outline text="Normal cell volume with iron plus B-twelve deficiency"/>
        <outline text="Reticulocytes corrected for severity and maturation"/>
        <outline text="Neutropenia risk: count, duration, barrier, immunity"/>
        <outline text="Sodium: water relative to exchangeable cations">
          <outline text="Acute severe low sodium: cerebral oedema"/>
          <outline text="Rapid chronic correction: osmotic demyelination"/>
        </outline>
        <outline text="Pseudohyperkalaemia from haemolysis, fist clenching">
          <outline text="Treat electrical instability while confirming"/>
          <outline text="Normal tracing does not make severe levels safe"/>
        </outline>
        <outline text="Magnesium deficiency: refractory potassium"/>
      </outline>
      <outline text="Kidney, liver, cardiac and endocrine markers">
        <outline text="Creatinine delayed and imperfect">
          <outline text="Estimated filtration assumes steady state"/>
        </outline>
        <outline text="Urine studies explain mechanism better"/>
        <outline text="Liver: injury, cholestasis, function">
          <outline text="Falling enzymes in failure: loss of viable cells"/>
        </outline>
        <outline text="Troponin proves myocardial injury">
          <outline text="Infarction needs rise or fall plus ischaemia"/>
        </outline>
        <outline text="Natriuretic peptides lower in obesity"/>
        <outline text="Endocrine tests measure feedback systems">
          <outline text="Treat suspected adrenal crisis before testing"/>
        </outline>
      </outline>
      <outline text="Coagulation and microbiology">
        <outline text="Screens sample limited pathways"/>
        <outline text="Mixing study: deficiency versus inhibitor"/>
        <outline text="Bleeding history outweighs indiscriminate screening"/>
        <outline text="Deep specimen before antibiotics establishes cause"/>
        <outline text="Superficial swabs report colonisers"/>
        <outline text="Nucleic-acid tests detect dead organisms and carriage"/>
        <outline text="In vitro susceptibility not penetration"/>
      </outline>
      <outline text="Imaging modalities and contrast">
        <outline text="Radiography: projection with overlap"/>
        <outline text="Point-of-care ultrasound is not a formal study"/>
        <outline text="CT: rapid anatomy, cumulative radiation"/>
        <outline text="Iodinated contrast: kidney risk depends on context">
          <outline text="Unrelated allergy does not prohibit contrast"/>
          <outline text="Premedication does not eliminate reactions"/>
        </outline>
        <outline text="Delay for theoretical renal risk can harm more"/>
        <outline text="Magnetic resonance not best just for no radiation"/>
      </outline>
      <outline text="Imaging choice and incidental findings">
        <outline text="Non-contrast CT for acute intracranial blood"/>
        <outline text="Diffusion imaging for early infarction"/>
        <outline text="Ultrasound first for gallstones"/>
        <outline text="CT angiography for mesenteric ischaemia"/>
        <outline text="Least harmful test that adequately answers"/>
        <outline text="Incidental findings: second diagnostic problem">
          <outline text="Avoid catastrophic language, never bury action"/>
        </outline>
        <outline text="Overdiagnosis: screening needs stronger evidence"/>
      </outline>
      <outline text="Longitudinal stewardship">
        <outline text="Stop daily panels that no longer guide care"/>
        <outline text="Repeat when trajectory is the signal"/>
        <outline text="Document reason, probability change, action, owner"/>
        <outline text="Record decisions not to test"/>
      </outline>
    </outline>
  </body>
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