To select a code in the classification that corresponds to a diagnosis or reason for visit documented in a medical record, first locate the term in the Alphabetic Index, and then verify the code in the Tabular List. It is essential to use both the Alphabetic Index and Tabular List when locating and assigning a code.
Diagnosis codes are to be used and reported at their highest number of characters available and to the highest level of specificity documented in the medical record. A code is invalid if it has not been coded to the full number of characters required for that code, including the 7th character, if applicable.
The appropriate code or codes from A00.0 through T88.9, Z00-Z99.8, and U00-U85 must be used to identify diagnoses, symptoms, conditions, problems, complaints or other reason(s) for the encounter/visit.
Codes that describe symptoms and signs, as opposed to diagnoses, are acceptable for reporting purposes when a related definitive diagnosis has not been established (confirmed) by the provider.
Signs and symptoms that are associated routinely with a disease process should not be assigned as additional codes, unless otherwise instructed by the classification.
Additional signs and symptoms that may not be associated routinely with a disease process should be coded when present.
In addition to the etiology/manifestation convention that requires two codes to fully describe a single condition that affects multiple body systems, there are other single conditions that also require more than one code.
If the same condition is described as both acute (subacute) and chronic, and separate subentries exist in the Alphabetic Index at the same indentation level, code both and sequence the acute (subacute) code first.
A combination code is a single code used to classify: Two diagnoses, or a diagnosis with an associated secondary process (manifestation), or a diagnosis with an associated complication.
A sequela is the residual effect (condition produced) after the acute phase of an illness or injury has terminated. There is no time limit on when a sequela code can be used.
Code any condition described at the time of discharge as "impending" or "threatened" as follows: If it did occur, code as confirmed diagnosis. If it did not occur, reference the Alphabetic Index to determine if the condition has a subentry term for "impending" or "threatened" and also reference main term entries for "Impending" and for "Threatened."
Each unique ICD-10-CM diagnosis code may be reported only once for an encounter. This applies to bilateral conditions when there are no distinct codes identifying laterality or two different conditions classified to the same ICD-10-CM diagnosis code.
Some ICD-10-CM codes indicate laterality, specifying whether the condition occurs on the left, right or is bilateral. If no bilateral code is provided and the condition is bilateral, assign separate codes for both the left and right side.
Code assignment is based on the documentation by the patient's provider (i.e., physician or other qualified healthcare practitioner legally accountable for establishing the patient's diagnosis). There are a few exceptions when code assignment may be based on medical record documentation from clinicians who are not the patient's provider.
Follow the Alphabetic Index guidance when coding syndromes. In the absence of Alphabetic Index guidance, assign codes for the documented manifestations of the syndrome. Additional codes for manifestations that are not an integral part of the disease process may also be assigned when the condition does not have a unique code.
Code assignment is based on the provider's documentation of the relationship between the condition and the care or procedure, unless otherwise instructed by the classification. It is not necessary for the provider to explicitly document the term "complication."
If the provider documents a "borderline" diagnosis at the time of discharge, the diagnosis is coded as confirmed, unless the classification provides a specific entry (e.g., borderline diabetes). If a borderline condition has a specific index entry in ICD-10-CM, it should be coded as such.
Sign/symptom and "unspecified" codes have acceptable, even necessary, uses. While specific diagnosis codes should be reported when they are supported by the available medical record documentation and clinical knowledge of the patient's health condition, there are instances when signs/symptoms or unspecified codes are the best choices for accurately reflecting the healthcare encounter.
This guideline provides specific instructions for coding healthcare encounters related to hurricane aftermath, including the use of external cause codes, sequencing of cataclysmic event codes, and the use of Z codes to explain reasons for healthcare services.