Pointer letters A–L followed by valid ICD-10-CM codes. The placeholder X is used where a 7th character is required but absent (e.g., K02.51K02 → K02.51X). Pointer letters reference diagnoses used in Box 24E.
The period between the letter and the code is dropped ("AK02.51" instead of "A. K02.51"). The required 7th character is omitted on injury codes (S, T, V, W, X, Y). Codes are listed without a pointer letter.