PCA CPP: ICD-10-CM Diagnosis Coding

What this domain tests

This domain tests the Alphabetic Index and Tabular List, conventions, combination codes, laterality, 7th characters, external causes, Z codes, and outpatient versus inpatient reporting rules.

Core rules

• Look up the term in the Index, verify the code in the Tabular List, and follow all notes at the category and code level.
• Excludes1 means the two conditions cannot be coded together; Excludes2 means the second condition is not included here but may be reported separately when documented.
• "Code first" identifies the underlying condition when a manifestation is present. "Use additional code" identifies a component that must be added.
• Outpatient settings do not code probable, suspected, or rule-out diagnoses; code the condition treated or evaluated. Inpatient settings code a qualified diagnosis as if established.
• Laterality and 7th characters (A initial encounter, D subsequent, S sequela) must match the record.

Worked example

A patient with type 2 diabetes has stage 3a chronic kidney disease. The Index directs diabetes, diabetic, kidney to E11.22. The Tabular note says to use an additional code for the CKD stage, so report E11.22 first and N18.31 second. Do not substitute N18.9, and do not add an unrelated diabetes code that would duplicate the combination.

Traps

Confusing Excludes1 with Excludes2; omitting a required additional code; dropping the 7th character; coding "history of" as active disease; stopping at the Index without Tabular verification; using an unspecified code when the record supports specificity.