John Hay
John Hay Biomedical
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My ClassGlossary
Genetics of Disease (Medical Interventions)
Unit 1: Clinical Reasoning LadderFeeds no tested domain

Clinical Reasoning 3: Take the history first

Most diagnoses are sitting in the patient's own account before any test is ordered. Learn the chief complaint, the follow-up question, and why doctors ask about systems you never mentioned.

Builds on (2 levels back)manual · high confidence
  • Telling a sign from a symptom: Rung 1 of the clinical ladder: a history is symptoms in the patient's words, and you need that category before you can collect it on purpose.

Re-learn the skill with worked practice and clear examples.

The conversation is the highest-yield part of the visit. Handled well, it settles most cases before a single order is written, which is why it comes first.

Step 1: Trust the yield
About two thirds of diagnoses can be made from the medical history alone, before the physical exam and before any laboratory work. The conversation is not the warm-up; it is the main event.
Step 2: Sharpen with follow-ups
Onset, duration, triggers, and what makes it better or worse. Each answer trims the space of causes, and the next question should chase the biggest remaining uncertainty.
Step 3: Listen past the script
Answers create the next question. A fixed list read straight through misses the thread the patient just handed you.
Practice

A clinic supervisor tells a student that most cases are already solvable before any order goes in. Which part of the visit was the supervisor pointing at?

Reviewed
  1. A.The conversation: roughly two thirds of diagnoses can be reached from the history alone
  2. B.The waiting room: watching patients walk in reveals most conditions before the visit
  3. C.The billing file: past invoices show which conditions this patient tends to develop
  4. D.The imaging: most conditions show up on a routine scan ordered in advance, before any of the talking needs to happen
Show the worked solution ▾

Answer: A. The conversation: roughly two thirds of diagnoses can be reached from the history alone

  1. Step 1: Recall the yield figure: The history alone settles about two of every three diagnoses, which is more than any single test contributes.
  2. Step 2: Test the rivals against practice: Scans are ordered because of what the conversation found, not before it. Billing shows costs, not causes. A walk through a doorway is a fraction of one finding.

Why it's right: The supervisor is quoting the standard teaching that about two thirds of diagnoses can be made from the medical history alone, which is why the conversation leads the visit.

Why the others miss:
  • B: Observation adds real clues, but nothing close to most of the answer.
  • C: Billing records carry charges and dates, not diagnostic evidence.
  • D: Imaging is chosen to answer questions the history raised; it does not come first.

Aligned to Clinical reasoning: yield of the history · reading level ~grade 9

Where you'd see this
  • Telemedicine runs almost entirely on this rung: with no hands and no lab in reach, the interview carries the whole visit.
Careers that use this
Physician Assistant: Builds the working problem from the interview first, then spends the exam and lab budget only on what the story left open.
Guided notes

Fill these in as you work through the lesson.

Big idea: The history is the highest-yield test in medicine and it costs only minutes: the chief complaint anchors it, follow-up questions sharpen it, and the review of systems catches what the patient never connected.
Key terms: write the meaning
  • Chief complaint (the main problem, in the patient's own account):  
  • Medical history (past and current health, habits, family):  
  • Review of systems (questions system by system, beyond the complaint):  
  • Follow-up question (sharpens onset, duration, triggers):  
The rule

The   complaint anchors the visit. About two   of diagnoses can be made from the history alone. The review of   hunts for evidence in systems the patient never mentioned.

Check yourself
  1. Turn 'my stomach hurts' into three follow-up questions about onset, duration, and triggers. 
  2. Why does a doctor ask a rash patient about joint pain? 
  3. What is lost when a clinician jumps straight to tests without the conversation? 
Work one example

A classmate volunteers 'I have been coughing.' Write the chief complaint as they said it, then five follow-up questions in the order you would ask them, and mark which two questions you expect to do the most narrowing.