Diagnostic Support Summaries
Overview
Generate comprehensive, evidence-based diagnostic summaries that synthesize a patient's clinical presentation, examination findings, and test results into structured differential diagnoses with supporting evidence. This skill applies validated diagnostic criteria, Bayesian clinical reasoning, and evidence-based medicine principles to support — not replace — physician diagnostic decision-making.
When to Use
- Synthesizing complex clinical presentations into structured differentials
- Preparing diagnostic case summaries for conferences or consultations
- Summarizing diagnostic workup progress with next-step recommendations
- Supporting clinical reasoning with evidence-based diagnostic criteria
- Generating teaching case summaries for medical education
- Documenting diagnostic reasoning for medical-legal purposes
Required Inputs
| Input | Description | Format | |-------|-------------|--------| | Clinical presentation | Symptoms, duration, progression, associated features | Structured HPI | | Physical exam findings | Pertinent positives and negatives by system | Structured exam | | Diagnostic test results | Labs, imaging, pathology, special tests | Structured results with reference ranges | | Patient context | Age, sex, comorbidities, medications, risk factors | Structured demographics | | Clinical question | Specific diagnostic question being addressed | Free text |
Methodology
Step 1: Clinical Data Organization
Structure the clinical information using a systematic framework:
Presenting Syndrome Identification:
- Identify the primary presenting syndrome (e.g., acute chest pain, chronic cough, unexplained weight loss)
- Classify by organ system, acuity (acute/subacute/chronic), and severity
- Note temporal pattern (sudden, gradual, intermittent, progressive)
Pertinent Feature Extraction:
- Pertinent positives: findings that support specific diagnoses
- Pertinent negatives: findings that argue against specific diagnoses
- Red flags: findings suggesting dangerous or emergent conditions
- Pattern recognition: classic presentation patterns (e.g., pleuritic chest pain + dyspnea + recent immobilization = PE concern)
Step 2: Differential Diagnosis Generation
Build a prioritized differential using anatomic, pathophysiologic, and probabilistic reasoning:
Framework: "VINDICATE + P"
- Vascular: thrombotic, embolic, hemorrhagic, vasculitic
- Infectious: bacterial, viral, fungal, parasitic
- Neoplastic: primary, metastatic, paraneoplastic
- Degenerative: wear-and-tear, aging-related
- Iatrogenic/Intoxication: drug-related, procedure-related
- Congenital: genetic, developmental
- Autoimmune/Allergic: systemic autoimmune, organ-specific
- Traumatic: acute injury, repetitive stress
- Endocrine/Metabolic: hormonal, electrolyte, metabolic
- Psychogenic: functional, somatoform, psychiatric
Step 3: Evidence Mapping
For each differential diagnosis, map the supporting and refuting evidence:
Diagnostic Criteria Application:
- Apply validated diagnostic criteria where available (e.g., Duke criteria for endocarditis, SLICC criteria for SLE, Light criteria for pleural effusion)
- Calculate pre-test probability using clinical prediction rules where applicable (Wells score for PE, CHA2DS2-VASc for stroke risk)
- Note sensitivity and specificity of key findings for each diagnosis
Evidence Strength for Each Diagnosis:
- Strong support: pathognomonic finding or multiple concordant features
- Moderate support: several consistent features, some expected features absent
- Weak support: possible but fewer consistent features
- Against: key expected features absent or contradictory findings present
Step 4: Workup Assessment
Evaluate the current diagnostic workup status:
- Completed tests: results and their diagnostic implications
- Pending tests: expected timeline and what they will clarify
- Recommended next tests: prioritized by diagnostic yield and clinical urgency
- Test characteristics: sensitivity, specificity, likelihood ratios for recommended tests
Step 5: Summary Generation
Produce the diagnostic support summary:
Summary Components:
- One-sentence clinical synopsis
- Ranked differential with probability estimates and evidence basis
- Key supporting/refuting evidence for top 3 diagnoses
- Current workup status with pending and recommended tests
- Clinical reasoning narrative connecting evidence to diagnoses
- Urgency assessment for time-sensitive diagnoses
Output Specification
The output includes:
clinical_synopsis: one-sentence summary of the case
presenting_syndrome: syndrome name, organ_system, acuity, severity
differential_diagnoses (ranked list): diagnosis name, icd10, probability_estimate (high/moderate/low/unlikely), supporting_evidence list, refuting_evidence list, diagnostic_criteria_met (criteria name, elements met, elements total), key_discriminating_tests
workup_status: completed_tests (test, result, interpretation, diagnostic_implication), pending_tests (test, expected_turnaround, diagnostic_question), recommended_tests (test, rationale, sensitivity, specificity, urgency)
clinical_reasoning_narrative: prose explaining the diagnostic logic
urgency_flags: time-sensitive diagnoses requiring immediate action
evidence_references: guideline or literature citations supporting the analysis
Analysis Framework
Diagnostic Probability Stratification
| Probability Tier | Estimated Likelihood | Action | |-----------------|---------------------|--------| | Must not miss | Any probability, high severity | Rule out immediately regardless of probability | | High probability | Greater than 50% | Primary working diagnosis, confirm | | Moderate probability | 15-50% | Active differential, targeted testing | | Low probability | 5-15% | Consider if initial workup negative | | Unlikely | Less than 5% | Do not pursue unless red flags emerge |
Pre-Test to Post-Test Probability
Apply likelihood ratios to update diagnostic probabilities:
- LR+ greater than 10: Strong rule-in (large increase in probability)
- LR+ 5-10: Moderate rule-in
- LR+ 2-5: Small increase in probability
- LR- 0.2-0.5: Small decrease in probability
- LR- 0.1-0.2: Moderate rule-out
- LR- less than 0.1: Strong rule-out (large decrease in probability)
Examples
Input: 45-year-old female presenting with 3 weeks of progressive fatigue, joint pain (MCPs and wrists bilateral), morning stiffness lasting over 60 minutes, and new malar rash. ANA positive 1:640, dsDNA positive, C3/C4 low, CBC shows mild leukopenia.
Diagnostic Summary (abbreviated):
- Synopsis: 45F with polyarthritis, malar rash, and serologic findings concerning for systemic lupus erythematosus
- Top Differential:
- SLE (HIGH) — meets 4+ SLICC criteria (arthritis, malar rash, ANA+, dsDNA+, low complement, leukopenia). Criteria: 4/11 ACR or 4/17 SLICC met
- Mixed connective tissue disease (LOW) — overlapping features but anti-U1 RNP not tested
- Rheumatoid arthritis (LOW) — symmetric small joint arthritis fits, but rash and serology favor SLE
- Recommended: anti-Smith antibody, anti-U1 RNP, urinalysis with microscopy (lupus nephritis screening), anti-CCP (RA differentiation), complement levels trending
- Urgency: Renal involvement screening is time-sensitive
Guidelines
- This is decision support, not diagnosis — all output requires physician review and clinical judgment
- Must-not-miss diagnoses always appear regardless of probability (e.g., PE in chest pain, SAH in headache)
- Apply Occam's razor judiciously — prefer one unifying diagnosis but acknowledge when multiple diagnoses are more likely
- Cite diagnostic criteria explicitly — specify which criteria are met and which are not
- Quantify uncertainty — use probability tiers rather than definitive statements
Validation Checklist
- [ ] All pertinent positives and negatives from the input are addressed
- [ ] Differential diagnoses are prioritized by probability and severity
- [ ] Must-not-miss diagnoses are included regardless of probability
- [ ] Diagnostic criteria are applied correctly with elements enumerated
- [ ] Recommended tests are prioritized by diagnostic yield and urgency
- [ ] Clinical reasoning narrative is logically coherent
- [ ] No diagnostic conclusions are stated as definitive — all framed as supportive
HIPAA Compliance Notes
- Diagnostic summaries contain sensitive PHI including diagnoses and test results
- When used for teaching or case conferences, fully de-identify per Safe Harbor (remove all 18 identifiers)
- Store diagnostic support outputs in the medical record system under appropriate access controls
- Ensure AI-generated diagnostic summaries are clearly labeled as decision support, not final diagnoses
- Maintain audit trails for all diagnostic summary generation and access
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