Mierau Medical Diagnostic and Coding Method
Postulate 5 Separation of Diagnosis and Classification
Statement
Diagnosis and classification SHALL be treated as separate stages of the medical reasoning process.
Definition
Diagnosis is the medical determination or assessment of a patient's condition based on the available medical information, findings, and clinical reasoning.
Classification is the subsequent assignment of that diagnosis or medical condition to a defined classification system.
Diagnosis answers:
What is medically present or most likely present?
Classification answers:
How is this medical determination represented within a classification system?
A classification system SHALL NOT be treated as a substitute for diagnostic reasoning.
Principle
A diagnosis SHALL be established independently of its classification whenever the diagnostic process permits. Classification SHALL follow diagnosis and SHALL NOT determine diagnosis.
The existence of a suitable classification entry does not establish that the corresponding diagnosis is medically justified.
Conversely, the absence of an immediately apparent classification entry does not invalidate an established medical finding or diagnosis.
Rationale
Classification systems are designed to organize and standardize medical information.
They are therefore useful for
- documentation,
- communication,
- statistics,
- administration,
- billing,
- and other purposes.
However, classification systems necessarily reduce complex medical reality to defined categories.
This creates a fundamental risk:
The available classification category may begin to influence the medical interpretation instead of merely representing it.
A diagnostic process must therefore not be reversed
classification → presumed diagnosis
instead of
medical reality → investigation → evidence → diagnosis → classification
This distinction is particularly important wherever classification is routinely required as part of medical documentation or administrative processes.
Practical Example
A patient states: "I have back pain."
A classification system may contain several potentially applicable categories.
Selecting one of these categories does not establish which medical condition is actually causing the patient's pain.
The appropriate sequence is
Patient report → medical assessment → appropriate investigation → diagnostic reasoning → diagnosis → classification
not
Patient report → classification software → selected diagnosis
A classification entry therefore remains a representation of a diagnostic decision, not the diagnostic decision itself.
Database Requirements
The database SHALL store diagnosis and classification as separate data elements.
The database SHOULD be able to distinguish
- diagnostic statement,
- diagnostic status,
- basis of the diagnosis,
- classification system,
- classification version,
- classification code,
- date of classification,
- and the relationship between the diagnosis and its classification.
A classification entry SHALL NOT overwrite or replace the underlying diagnostic statement.
Implications
This principle means
- a code is not a diagnosis.
- a classification category is not evidence of diagnostic certainty.
- Selecting a code SHALL NOT be treated as establishing the underlying medical condition.
- Diagnostic reasoning SHALL remain possible independently of the classification system.
- Classification may occur after diagnosis without altering the underlying diagnostic reasoning.
- Where a diagnosis changes, its classification may need to be revised accordingly.
This principle also creates an important safeguard for longitudinal records:
Repeated classification of the same diagnosis does not constitute repeated independent confirmation of that diagnosis.
Related Postulates
P4 — Primacy of Medical Reality
establishes that medical reality takes precedence over its representation.
P6 — Knowledge Principle
requires diagnostic assessments to be understood within the knowledge available at the relevant time.
P8 — Investigation Principle
addresses how investigations contribute to diagnostic reasoning.
P9 — Evidence Principle
addresses the evidentiary basis for diagnostic conclusions.
P17 — Version Principle
becomes relevant when a diagnosis is subsequently assigned to a particular version of a classification system.
Key Message
Diagnose first. Classify afterwards.
Mierau Medical Diagnostic and Coding Method
Postulate 5 Separation of Diagnosis and Classification
Statement
Diagnosis and classification SHALL be treated as separate stages of the medical reasoning process.
Definition
Diagnosis is the medical determination or assessment of a patient's condition based on the available medical information, findings, and clinical reasoning.
Classification is the subsequent assignment of that diagnosis or medical condition to a defined classification system.
Diagnosis answers:
What is medically present or most likely present?
Classification answers:
How is this medical determination represented within a classification system?
A classification system SHALL NOT be treated as a substitute for diagnostic reasoning.
Principle
A diagnosis SHALL be established independently of its classification whenever the diagnostic process permits. Classification SHALL follow diagnosis and SHALL NOT determine diagnosis.
The existence of a suitable classification entry does not establish that the corresponding diagnosis is medically justified.
Conversely, the absence of an immediately apparent classification entry does not invalidate an established medical finding or diagnosis.
Rationale
Classification systems are designed to organize and standardize medical information.
They are therefore useful for
- documentation,
- communication,
- statistics,
- administration,
- billing,
- and other purposes.
However, classification systems necessarily reduce complex medical reality to defined categories.
This creates a fundamental risk:
The available classification category may begin to influence the medical interpretation instead of merely representing it.
A diagnostic process must therefore not be reversed
classification → presumed diagnosis
instead of
medical reality → investigation → evidence → diagnosis → classification
This distinction is particularly important wherever classification is routinely required as part of medical documentation or administrative processes.
Practical Example
A patient states: "I have back pain."
A classification system may contain several potentially applicable categories.
Selecting one of these categories does not establish which medical condition is actually causing the patient's pain.
The appropriate sequence is
Patient report → medical assessment → appropriate investigation → diagnostic reasoning → diagnosis → classification
not
Patient report → classification software → selected diagnosis
A classification entry therefore remains a representation of a diagnostic decision, not the diagnostic decision itself.
Database Requirements
The database SHALL store diagnosis and classification as separate data elements.
The database SHOULD be able to distinguish
- diagnostic statement,
- diagnostic status,
- basis of the diagnosis,
- classification system,
- classification version,
- classification code,
- date of classification,
- and the relationship between the diagnosis and its classification.
A classification entry SHALL NOT overwrite or replace the underlying diagnostic statement.
Implications
This principle means
- a code is not a diagnosis.
- a classification category is not evidence of diagnostic certainty.
- Selecting a code SHALL NOT be treated as establishing the underlying medical condition.
- Diagnostic reasoning SHALL remain possible independently of the classification system.
- Classification may occur after diagnosis without altering the underlying diagnostic reasoning.
- Where a diagnosis changes, its classification may need to be revised accordingly.
This principle also creates an important safeguard for longitudinal records:
Repeated classification of the same diagnosis does not constitute repeated independent confirmation of that diagnosis.
Related Postulates
P4 — Primacy of Medical Reality
establishes that medical reality takes precedence over its representation.
P6 — Knowledge Principle
requires diagnostic assessments to be understood within the knowledge available at the relevant time.
P8 — Investigation Principle
addresses how investigations contribute to diagnostic reasoning.
P9 — Evidence Principle
addresses the evidentiary basis for diagnostic conclusions.
P17 — Version Principle
becomes relevant when a diagnosis is subsequently assigned to a particular version of a classification system.
Key Message
Diagnose first. Classify afterwards.
Mierau Medical Diagnostic and Coding Method
Postulate 5 Separation of Diagnosis and Classification
Statement
Diagnosis and classification SHALL be treated as separate stages of the medical reasoning process.
Definition
Diagnosis is the medical determination or assessment of a patient's condition based on the available medical information, findings, and clinical reasoning.
Classification is the subsequent assignment of that diagnosis or medical condition to a defined classification system.
Diagnosis answers:
What is medically present or most likely present?
Classification answers:
How is this medical determination represented within a classification system?
A classification system SHALL NOT be treated as a substitute for diagnostic reasoning.
Principle
A diagnosis SHALL be established independently of its classification whenever the diagnostic process permits. Classification SHALL follow diagnosis and SHALL NOT determine diagnosis.
The existence of a suitable classification entry does not establish that the corresponding diagnosis is medically justified.
Conversely, the absence of an immediately apparent classification entry does not invalidate an established medical finding or diagnosis.
Rationale
Classification systems are designed to organize and standardize medical information.
They are therefore useful for
- documentation,
- communication,
- statistics,
- administration,
- billing,
- and other purposes.
However, classification systems necessarily reduce complex medical reality to defined categories.
This creates a fundamental risk:
The available classification category may begin to influence the medical interpretation instead of merely representing it.
A diagnostic process must therefore not be reversed
classification → presumed diagnosis
instead of
medical reality → investigation → evidence → diagnosis → classification
This distinction is particularly important wherever classification is routinely required as part of medical documentation or administrative processes.
Practical Example
A patient states: "I have back pain."
A classification system may contain several potentially applicable categories.
Selecting one of these categories does not establish which medical condition is actually causing the patient's pain.
The appropriate sequence is
Patient report → medical assessment → appropriate investigation → diagnostic reasoning → diagnosis → classification
not
Patient report → classification software → selected diagnosis
A classification entry therefore remains a representation of a diagnostic decision, not the diagnostic decision itself.
Database Requirements
The database SHALL store diagnosis and classification as separate data elements.
The database SHOULD be able to distinguish
- diagnostic statement,
- diagnostic status,
- basis of the diagnosis,
- classification system,
- classification version,
- classification code,
- date of classification,
- and the relationship between the diagnosis and its classification.
A classification entry SHALL NOT overwrite or replace the underlying diagnostic statement.
Implications
This principle means
- a code is not a diagnosis.
- a classification category is not evidence of diagnostic certainty.
- Selecting a code SHALL NOT be treated as establishing the underlying medical condition.
- Diagnostic reasoning SHALL remain possible independently of the classification system.
- Classification may occur after diagnosis without altering the underlying diagnostic reasoning.
- Where a diagnosis changes, its classification may need to be revised accordingly.
This principle also creates an important safeguard for longitudinal records:
Repeated classification of the same diagnosis does not constitute repeated independent confirmation of that diagnosis.
Related Postulates
P4 — Primacy of Medical Reality
establishes that medical reality takes precedence over its representation.
P6 — Knowledge Principle
requires diagnostic assessments to be understood within the knowledge available at the relevant time.
P8 — Investigation Principle
addresses how investigations contribute to diagnostic reasoning.
P9 — Evidence Principle
addresses the evidentiary basis for diagnostic conclusions.
P17 — Version Principle
becomes relevant when a diagnosis is subsequently assigned to a particular version of a classification system.
Key Message
Diagnose first. Classify afterwards.
Mierau Medical Diagnostic and Coding Method
Postulate 5 Separation of Diagnosis and Classification
Statement
Diagnosis and classification SHALL be treated as separate stages of the medical reasoning process.
Definition
Diagnosis is the medical determination or assessment of a patient's condition based on the available medical information, findings, and clinical reasoning.
Classification is the subsequent assignment of that diagnosis or medical condition to a defined classification system.
Diagnosis answers:
What is medically present or most likely present?
Classification answers:
How is this medical determination represented within a classification system?
A classification system SHALL NOT be treated as a substitute for diagnostic reasoning.
Principle
A diagnosis SHALL be established independently of its classification whenever the diagnostic process permits. Classification SHALL follow diagnosis and SHALL NOT determine diagnosis.
The existence of a suitable classification entry does not establish that the corresponding diagnosis is medically justified.
Conversely, the absence of an immediately apparent classification entry does not invalidate an established medical finding or diagnosis.
Rationale
Classification systems are designed to organize and standardize medical information.
They are therefore useful for
- documentation,
- communication,
- statistics,
- administration,
- billing,
- and other purposes.
However, classification systems necessarily reduce complex medical reality to defined categories.
This creates a fundamental risk:
The available classification category may begin to influence the medical interpretation instead of merely representing it.
A diagnostic process must therefore not be reversed
classification → presumed diagnosis
instead of
medical reality → investigation → evidence → diagnosis → classification
This distinction is particularly important wherever classification is routinely required as part of medical documentation or administrative processes.
Practical Example
A patient states: "I have back pain."
A classification system may contain several potentially applicable categories.
Selecting one of these categories does not establish which medical condition is actually causing the patient's pain.
The appropriate sequence is
Patient report → medical assessment → appropriate investigation → diagnostic reasoning → diagnosis → classification
not
Patient report → classification software → selected diagnosis
A classification entry therefore remains a representation of a diagnostic decision, not the diagnostic decision itself.
Database Requirements
The database SHALL store diagnosis and classification as separate data elements.
The database SHOULD be able to distinguish
- diagnostic statement,
- diagnostic status,
- basis of the diagnosis,
- classification system,
- classification version,
- classification code,
- date of classification,
- and the relationship between the diagnosis and its classification.
A classification entry SHALL NOT overwrite or replace the underlying diagnostic statement.
Implications
This principle means
- a code is not a diagnosis.
- a classification category is not evidence of diagnostic certainty.
- Selecting a code SHALL NOT be treated as establishing the underlying medical condition.
- Diagnostic reasoning SHALL remain possible independently of the classification system.
- Classification may occur after diagnosis without altering the underlying diagnostic reasoning.
- Where a diagnosis changes, its classification may need to be revised accordingly.
This principle also creates an important safeguard for longitudinal records:
Repeated classification of the same diagnosis does not constitute repeated independent confirmation of that diagnosis.
Related Postulates
P4 — Primacy of Medical Reality
establishes that medical reality takes precedence over its representation.
P6 — Knowledge Principle
requires diagnostic assessments to be understood within the knowledge available at the relevant time.
P8 — Investigation Principle
addresses how investigations contribute to diagnostic reasoning.
P9 — Evidence Principle
addresses the evidentiary basis for diagnostic conclusions.
P17 — Version Principle
becomes relevant when a diagnosis is subsequently assigned to a particular version of a classification system.
Key Message
Diagnose first. Classify afterwards.
Mierau Medical Diagnostic and Coding Method
Postulate 5 Separation of Diagnosis and Classification
Statement
Diagnosis and classification SHALL be treated as separate stages of the medical reasoning process.
Definition
Diagnosis is the medical determination or assessment of a patient's condition based on the available medical information, findings, and clinical reasoning.
Classification is the subsequent assignment of that diagnosis or medical condition to a defined classification system.
Diagnosis answers:
What is medically present or most likely present?
Classification answers:
How is this medical determination represented within a classification system?
A classification system SHALL NOT be treated as a substitute for diagnostic reasoning.
Principle
A diagnosis SHALL be established independently of its classification whenever the diagnostic process permits. Classification SHALL follow diagnosis and SHALL NOT determine diagnosis.
The existence of a suitable classification entry does not establish that the corresponding diagnosis is medically justified.
Conversely, the absence of an immediately apparent classification entry does not invalidate an established medical finding or diagnosis.
Rationale
Classification systems are designed to organize and standardize medical information.
They are therefore useful for
- documentation,
- communication,
- statistics,
- administration,
- billing,
- and other purposes.
However, classification systems necessarily reduce complex medical reality to defined categories.
This creates a fundamental risk:
The available classification category may begin to influence the medical interpretation instead of merely representing it.
A diagnostic process must therefore not be reversed
classification → presumed diagnosis
instead of
medical reality → investigation → evidence → diagnosis → classification
This distinction is particularly important wherever classification is routinely required as part of medical documentation or administrative processes.
Practical Example
A patient states: "I have back pain."
A classification system may contain several potentially applicable categories.
Selecting one of these categories does not establish which medical condition is actually causing the patient's pain.
The appropriate sequence is
Patient report → medical assessment → appropriate investigation → diagnostic reasoning → diagnosis → classification
not
Patient report → classification software → selected diagnosis
A classification entry therefore remains a representation of a diagnostic decision, not the diagnostic decision itself.
Database Requirements
The database SHALL store diagnosis and classification as separate data elements.
The database SHOULD be able to distinguish
- diagnostic statement,
- diagnostic status,
- basis of the diagnosis,
- classification system,
- classification version,
- classification code,
- date of classification,
- and the relationship between the diagnosis and its classification.
A classification entry SHALL NOT overwrite or replace the underlying diagnostic statement.
Implications
This principle means
- a code is not a diagnosis.
- a classification category is not evidence of diagnostic certainty.
- Selecting a code SHALL NOT be treated as establishing the underlying medical condition.
- Diagnostic reasoning SHALL remain possible independently of the classification system.
- Classification may occur after diagnosis without altering the underlying diagnostic reasoning.
- Where a diagnosis changes, its classification may need to be revised accordingly.
This principle also creates an important safeguard for longitudinal records:
Repeated classification of the same diagnosis does not constitute repeated independent confirmation of that diagnosis.
Related Postulates
P4 — Primacy of Medical Reality
establishes that medical reality takes precedence over its representation.
P6 — Knowledge Principle
requires diagnostic assessments to be understood within the knowledge available at the relevant time.
P8 — Investigation Principle
addresses how investigations contribute to diagnostic reasoning.
P9 — Evidence Principle
addresses the evidentiary basis for diagnostic conclusions.
P17 — Version Principle
becomes relevant when a diagnosis is subsequently assigned to a particular version of a classification system.
Key Message
Diagnose first. Classify afterwards.
Mierau Medical Diagnostic and Coding Method
Postulate 5 Separation of Diagnosis and Classification
Statement
Diagnosis and classification SHALL be treated as separate stages of the medical reasoning process.
Definition
Diagnosis is the medical determination or assessment of a patient's condition based on the available medical information, findings, and clinical reasoning.
Classification is the subsequent assignment of that diagnosis or medical condition to a defined classification system.
Diagnosis answers:
What is medically present or most likely present?
Classification answers:
How is this medical determination represented within a classification system?
A classification system SHALL NOT be treated as a substitute for diagnostic reasoning.
Principle
A diagnosis SHALL be established independently of its classification whenever the diagnostic process permits. Classification SHALL follow diagnosis and SHALL NOT determine diagnosis.
The existence of a suitable classification entry does not establish that the corresponding diagnosis is medically justified.
Conversely, the absence of an immediately apparent classification entry does not invalidate an established medical finding or diagnosis.
Rationale
Classification systems are designed to organize and standardize medical information.
They are therefore useful for
- documentation,
- communication,
- statistics,
- administration,
- billing,
- and other purposes.
However, classification systems necessarily reduce complex medical reality to defined categories.
This creates a fundamental risk:
The available classification category may begin to influence the medical interpretation instead of merely representing it.
A diagnostic process must therefore not be reversed
classification → presumed diagnosis
instead of
medical reality → investigation → evidence → diagnosis → classification
This distinction is particularly important wherever classification is routinely required as part of medical documentation or administrative processes.
Practical Example
A patient states: "I have back pain."
A classification system may contain several potentially applicable categories.
Selecting one of these categories does not establish which medical condition is actually causing the patient's pain.
The appropriate sequence is
Patient report → medical assessment → appropriate investigation → diagnostic reasoning → diagnosis → classification
not
Patient report → classification software → selected diagnosis
A classification entry therefore remains a representation of a diagnostic decision, not the diagnostic decision itself.
Database Requirements
The database SHALL store diagnosis and classification as separate data elements.
The database SHOULD be able to distinguish
- diagnostic statement,
- diagnostic status,
- basis of the diagnosis,
- classification system,
- classification version,
- classification code,
- date of classification,
- and the relationship between the diagnosis and its classification.
A classification entry SHALL NOT overwrite or replace the underlying diagnostic statement.
Implications
This principle means
- a code is not a diagnosis.
- a classification category is not evidence of diagnostic certainty.
- Selecting a code SHALL NOT be treated as establishing the underlying medical condition.
- Diagnostic reasoning SHALL remain possible independently of the classification system.
- Classification may occur after diagnosis without altering the underlying diagnostic reasoning.
- Where a diagnosis changes, its classification may need to be revised accordingly.
This principle also creates an important safeguard for longitudinal records:
Repeated classification of the same diagnosis does not constitute repeated independent confirmation of that diagnosis.
Related Postulates
P4 — Primacy of Medical Reality
establishes that medical reality takes precedence over its representation.
P6 — Knowledge Principle
requires diagnostic assessments to be understood within the knowledge available at the relevant time.
P8 — Investigation Principle
addresses how investigations contribute to diagnostic reasoning.
P9 — Evidence Principle
addresses the evidentiary basis for diagnostic conclusions.
P17 — Version Principle
becomes relevant when a diagnosis is subsequently assigned to a particular version of a classification system.
Key Message
Diagnose first. Classify afterwards.