What do the A, D and S code mean?

The Tricky "7th" Character (Initial vs. Subsequent Encounter) One significant difference between ICD-9 and ICD-10 is the need to assign a 7th character, also called a 7th character extension, to codes in certain ICD-10-CM categories.These 7th character extensions are found predominantly in two chapters of the ICD-10-CM/PCS (International Classification of Diseases, 10th Edition, Clinical Modification/Procedure Coding System), Chapter 19 - Injury, Poisoning and Certain Other Consequences of External Causes, which includes the "S" codes, and also in Chapter 15 - Pregnancy, Childbirth and the Puerperium.This information only addresses the use of the 7th character for Chapter 19.A seventh character must be assigned to codes in the "S" category(injury, poisoning, and certain other consequences of external causes) to provide information about the episode of care.

A = Initial encounter

D = Subsequent encounter

S = Sequela (complications that arise as a direct result of a condition)

CMS has provided the following information regarding episodes of care:

"A" (Initial encounter) - Initial encounter is defined as the period when the patient is receiving active treatment for the injury, poisoning, or other consequences of an external cause. An "A" may be assigned on more than one claim.

"D" (Subsequent encounter) - An encounter after the active phase of treatment and when the patient is receiving routine care for the injury during the period of healing or recovery.

"S" (Sequela) - Complications that arise as a direct result of a condition.

Important note - initial vs. subsequent encounter:

At this time it appears that chiropractors should use the 'A' with injury codes for as long as they deem the patient to be receiving "active treatment" (that is, as long as the patient continues to progress). When the patient ceases to progress (when MMI has been reached) but the physician continues treatment to facilitate healing, then the 'D' should be applied. As a general rule, when the code requires a 'D', it would indicate a non-covered service.