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Understanding ICD-10-CM Episode of Care Seventh-Character Extensions

Written By Laui Gray, RHIT, CPC

To begin, let’s look at similarities and differences between the format and structure of ICD-9-CM and ICD-10-CM.



Three digit categories

Three character categories

Four digit subcategories

Four or five character subcategories

Five digit subclassifications

No subclassifications

Three-, four- or five-digit codes

Three, four, five, six or seven character codes

One significant difference between ICD-9-CM and ICD-10-CM is the need to assign a seventh character (also called a seventh-character extension) to codes in certain ICD-10-CM categories. These seventh characters are found predominantly in two chapters: Chapter 19 (Injury, Poisoning and Certain Other Consequences of External Causes) and Chapter 15 (Pregnancy, Childbirth and the Puerperium). The details captured with these extra characters are not details recorded under ICD-9-CM.

For injuries, poisonings and other external causes, the seventh character provides information about episodes of care; for pregnancy, childbirth and the puerperium, it provides information about the fetus. More specifically, the two types of seventh-character extensions provide information as follows:

  • Episode of care: designates the episode of care as initial, subsequent or a sequela for injuries, poisonings and certain other conditions; in some instances it also provides additional information about the diagnosis.
  • Fetus: used to identify certain complications of pregnancy with multiple gestation to denote which fetus(es) is(are) affected by the condition indicated by the code.

The seventh character typically is required for all codes in these categories, but instructions in each category should be reviewed for any exceptions. The seventh character always occupies the seventh-character data field, even for codes that have fewer than six characters. For codes of three to five characters, the placeholder “X” is used to fill in the empty character fields. In this article the seventh-character extensions that provide information about episode of care are reviewed.

Episode of Care

The episode-of-care seventh characters are used primarily for injuries, poisonings and other consequences of external causes; there are three seventh-character extensions for most of these conditions, with the exception of fractures. These include:

Initial encounter (“A”): initial encounter is defined as the period when a patient is receiving active treatment for an injury, poisoning or other consequences of an external cause. An “A” may be assigned on more than one claim. For example, consider a patient seen in the emergency department (ED) for a head injury that first is evaluated by an ED physician. If the ED physician requests a CT scan that subsequently is read by a radiologist and a neurologist, the seventh character “A” is used by all three physicians and also reported on the ED claim. If the patient required admission to an acute-care hospital, the seventh character would be reported for the entire acute-care hospital stay because “A” is used for the entire period when the patient receives active treatment.

Subsequent encounter (“D”): this is an encounter occurring after the active phase of treatment, when a patient is receiving routine care during a period of healing or recovery. For example, a patient with an ankle sprain may return to the office to have joint stability re-evaluated to ensure that the injury is healing properly. In this case, the seventh character “D” would be assigned.