First Basic Principle
Both the Alphabetic Index and the Tabular List must be used to locate and assign appropriate codes.
-First, locate in the Index the diagnosis, condition, or reason for visit; the code provided must be verified in the Tabular List.
-The Index does not provide the full code selection of the full code, including laterality and any applicable seventh character, can only be done using the tabular list.
-Follow instructional notes to determine that more specific subterms or important instructional notes are not overlooked.
Consistent reference to the Alphabetic Index and the Tabular List is imperative, no matter how experienced the coder is.
Second basic principle
Codes must be used to the highest number of characters available.
Steps for assigning codes to the highest level of detail:
- Assign a three-character disease code only if it is not further divided (when there are no four character codes within that category)
- Assign a four character code only when there are no five character codes within that sub category
- Assign a five-character code only when there are no six character codes for that subcategory.
- Assign a six character code when a sixth character subclassification is provided.
- Assign a seventh character value when provided.
All characters must be used. None can be omitted and none can be added EXCEPT
placeholder character “x”
Placeholder Character “x”
-For codes less than six characters that require a seventh character, a placeholder “x” should be assigned for all characters less than six
-The seventh character must always be the seventh character of a code
—example: Categories T36-T50 poisoning, adverse effects and underdosing codes.
Category J40, Bronchitis
-not specified as acute or chronic
-CODE J40 has no fourth character subdivisions, therefore the 3 character code is assigned
Category K35, Acute appendicitis
This category includes fourth characters that indicate the presence of generalized or localized peritonitis. Because fourth character subdivisions are provided, code K35 cannot be assigned.
Category J45, Asthma
-has five fourth character subdivisions (J45.2, J45.3, J45.4, J45.5 and J45.9
-It also uses a final character (fifth- or sixth- character) subclassification to specify whether there is any mention of status asthmaticus or acute exacerbation.
-Any code assignment from category J45 must have five characters (for subcategories j45.2-j45.5) or six characters for subcategory (J45.9) to ensure coding accuracy
T27, Burn and corrosion of respiratory tract,
-has eight four-character subdivisions to specify burn or corrosion and detail on the part of the respiratory tract affected.
-General note indicates seventh character to be added.
-Category T27 subcategories are only four characters long; the placeholder character “x” is used as a fifth- and sixth- character placeholder before the seventh character can be added
—Example: T27.0xxA for initial encounter for burn of the larynx and trachea.
the main term entry in the Alphabetic Index is usually followed by the
code number for the unspecified condition
The unspecified code should never be assigned without a
careful review of subterms to determine whether a more specific code can be located.
A single code used to classify any of the following:
-A diagnosis with an associated secondary condition
-A diagnosis with an associated complication
Combination codes can be located in the index with reference to subterms that follow connecting words such as;
“with” “due to” “in” and “Associated with”
Other combination codes can be found in
inclusion and exclusion notes in the Tabular List
Only the combination code is assigned when that code fully identifies the
diagnostic conditions involved or when the Alphabetic Index so directs
When a combination code lacks the necessary specificity in describing the manifestation or complication an
additional code may be assigned
is the use of more than one code to fully identify the component elements of a complex diagnostic or procedural statement.
A complex statement is
one with connecting words or phrases such as “with” “due to” “incidental to” “Secondary to” or similar terminology
If no combination code is provided –
assign multiple codes as needed to fully describe the condition regardless of whether there is advice to that effect.
The term “dual classification” is used to describe
The required assignment of two codes to provide information about both a manifestation and the associated underlying disease or etiology (if present)
Mandatory multiple coding is identified in the Alphabetic Index by
the use of a second code in brackets
-the first code identifies the underlying condition.
-the second code identifies the manifestation
-Both codes must be assigned and sequenced in the order listed.
The need for dual coding is indicated in the Tabular List by
-a “use additional code” note with the code for the underlying condition, and
a “code first underlying condition” note with the manifestation code.
-In printed versions of the manuals the manifestation code is in italics
Manifestation codes cannot be the principal diagnosis, a code for the underlying condition must always be listed first, except for an occasional situation where other directions are provided.
A code in brackets in the alphabetic Index can be used only
as a secondary code for the specific condition or procedure indexed in this way. Example: G20+F02,80 Dementia in Parkinson’s Disease
When there is a “code first” note and an underlying condition is present, the underlying condition should be sequenced first
Example: Malignant ascites (R18.0) has a note to “code first” the malignancy, such as malignant neoplasm of ovary (C56.-)
—Assign first C56.-, followed by code R18.0
The “code, if applicable, any causal condition first” note indicates
that multiple codes should be assigned only if the causal condition is documented as being present
Example of “Code if applicable any causal condition first”
“Other retention of urine” (R33.8) requires that the code to identify enlarged prostate (N40.1) be assigned as the first-listed code or principal diagnosis, but only if enlarged prostate is documented as being the cause of the urinary retention.
“Use additional code” indicates that
multiple codes should be assigned only if the condition mentioned is documented as being present
Example of “use additional code”
Urinary tract infection (N39.0) requires an additional code to identify the organism if it is documented, such as positive culture of E.coli (B96.20)
Indiscriminate coding of irrelevant information should be avoided – for example:
codes for symptoms and signs characteristics of the diagnosis and integral to it should not be assigned
Codes are never assigned solely on the basis of findings of diagnostic tests, such as laboratory, x-ray, or electrocardiographic tests, unless the diagnosis is
confirmed by the physician
-this differs from the coding encounters for diagnostic tests that have been interpreted by a physician
Codes should not be assigned for conditions that do not meet UHDDS criteria for reporting
Assigning a code is inappropriate for reporting purposes unless the physician provides documentation to support the condition’s significance for the episode of care.
Codes designated as unspecified are never assigned when
a more specific code for the same general condition is assigned
example: diabetes mellitus with unspecified complication (E11.8) would never be assigned when a code for diabetes with renal complication (E11.29) is assigned for the same episode of care
Some ICD-10-CM codes indicate laterality specifiying
whether the condition occurs on the left or right, or whether is is bilateral
if the condition is bilateral but no bilateral code is provided
assign separate codes for both the left and right sides
if the side is not identified in the medical record assign the code for
When a diagnosis for an inpatient to a short-term, acute care hospital, a long-term care hospital, or a psychiatric hospital is qualified as “possible,” “probable” “suspected” “likely” “questionable” “?” or “rule out” at the time of discharge the condition should be coded and reported as
though the diagnosis were established
For HIV infection/illness and influenza due to certain identified influenza viruses (eg avian influenza or other novel influenza A virus)
code only cases confirmed by physician documentation
For outpatients, home health services, or hospice services:
the first listed diagnosis for these encounters is coded to the highest degree of certainty, such as symptoms, signs or abnormalities.
For physician services regardless of the setting, coders should be guided by the
Diagnostic Coding and Reporting Guidelines for Outpatient Services (Hospital-Based and Physician Office)
Use caution in coding uncertain diagnoses of conditions such as epilepsy, HIV disease, and multiple sclerosis as if they were established:
-Incorrect reporting of such conditions can have serious personal consequences for the patient
-Consult the physician before assigning codes for such uncertain conditions
the diagnosis is still considered to be possible at the time of inpatient discharge
–code as if established for inpatient episodes of care in the same way that diagnoses described as possible or probable are coded
a diagnosis originally considered as likely is no longer a possibility at the time of inpatient discharge
–never code a diagnosis documented as “Ruled out”
–if an alternative condition has been identified, that diagnosis should be coded; otherwise, assign a code for the presenting symptom or other precursor condition.
-Care should be exercised with “borderline” diagnoses
–They are not the same as uncertain diagnoses.
—No distinction is made between the care setting (inpateint versus outpatient)
-Code as confirmed, unless the classification provides a specific entry(eg borderline diabetes mellitus)
-If the borderline condition has a specific index entry, code it as such
-Whenever teh documentation is unclear regarding a borderline condition, coders are encouraged to query for clarification
When the same condition is described as both acute (or sub acute) and chronic, it should be coded
according to the Alphabetic Index sub entries for that condition
If separate sub terms for acute (or sub acute) and chronic are listed at the same indention level in the Alphabetic Index –
both codes are assigned, with the code for the acute condition sequenced first
A condition described as subacute is coded as acute if there is
no separate sub term entry for sub acute.
When only one term is listed as a sub term, with the other in parentheses as a non essential modifier,
only the code listed for the sub term is assigned
Combination codes may be provided when
the condition is described as both acute and chronic
When there are no sub entries for acute ( or subacute) or chronic
these modifiers are disregarded in coding the condition.
The use of sign/symptom and “unspecified” codes is acceptable, even necessary as in the following situations;
-If a definitive diagnosis has not been established by the end of the encounter
-When sufficient clinical information is not known or available about a particular health condition to assign a more specific code
Unspecified codes should be reported when they are the codes that most accurately reflect what is known about the patient’s condition at the time of the encounter
Code selection depends first on whether the condition actually occurred. If it did..
the threatened/impending condition is coded as a confirmed diagnosis.
If neither the threatened/impending condition nor a related condition occurred,
the coder must refer to the Alphabetic Index
-Is the condition indexed under the main term a threatened or impending condition?
-Is there a subterm for impending or threatened under the main term for the condition?
-When neither term is indexed, the precursor condition that actually existed is coded; a code is not assigned for the condition described as impending or threatened.
Each unique ICD-10-CM diagnosis code may be reported only once for an encounter
-This applies to bilateral conditions
-This also applies to two different conditions classified to the same ICD-10-CM diagnosis code
-Residual Condition remaining after the termination of the acute phase of an illness or injury
-May occur at any time after an acute injury or illness
–There is no set period of time that must elapse before a condition is considered to be a late effect
-Include conditions reported as such or as sequela of a previous illness or injury.
-May be inferred with the following terms
–Due to previous injury or illness
–Following previous injury or illness
–Traumatic, unless there is evidence of current injury
Locating cause of late effect codes
-Refer to the main term “Sequelae” in the Alphabetic Index of Diseases and Injuries
–Exception: Late effects due to injury, poisoning, and certain other consequences of external causes
-ICD-10-CM provides only a limited number of codes to indicate the cause of a late effect
Complete coding of late effects requires two codes:
-The condition or nature of the late effect
-The late effect code
The condition or nature of the late effect is sequenced first, followed by the code for the cause of the late effect, except in a few instances where the Alphabetic Index or the Tabular List directs otherwise.
If the late effect is due to injury, poisoning, or certain other consequences of external causes (S00-T88) a seventh character value for sequelae should be assigned to the injury code as well as the external causes code (V01-Y95)
Exception to Two Codes for Late Effect
-When the residual effect is not stated, the cause of late effect code is used alone
-When no late effect code is provided but the condition is described as being a late effect, code only the residual condition
–Note that conditions described as due to previous surgery are not coded as late effects. They are classified as history of or complications of previous surgery, depending on the specific situation.
-When the late effect code has been expanded at the fourth- fifth- or sixth character level(S) to include the manifestation condition, only the cause of the late effect code is assigned.
–Example I69.01, Cognitive deficits following nontraumatic subarachnoid hemorrhage.
Do not use a late effect code with a code for a current injury or illness of the same type, with one exception:
Codes from category I69, Sequelae of cerebrovascular disease, may be assigned as an additional code with codes from I60-I67, if the patient has a current cerebrovascular disease and residual deficits from an old cerebrovascular disease.