Pathology/Lab Coding Alert

Question: I heard that we would have a new ICD-9 code this year for transfusion reactions other than ABO incompatibility, but I don't see a new code. Should we continue to report minor blood group antigen reactions as 999.6?

Texas Subscriber

Answer: No, you should not continue to report minor blood group antigen transfusion reactions such as Duffy, Kell, or Lewis, as 999.6 (ABO incompatibility reaction). Instead, you should be using 999.89 as of Oct. 1.

Although you are correct that ICD-9 2010 does not add a new code for these reactions, as proposed, a change in the ICD-9 index and a new "excludes" note under 999.6 should point you in the right direction.

Old way: When you looked up "transfusion, blood, incompatible" in the 2009 ICD-9 alphabetic index, the entry directed you to 999.6.

New way: When you look up the same entry in the 2010 ICD-9 alphabetic index, you'll see two entries directing you to two different codes:

• Transfusion, blood, incompatible, ABO -- 999.6

Once you turn to the tabular list for these codes, you'll get even more information. Under 999.6, ICD-9 2010 adds this note: "Excludes minor blood group antigens reactions (Duffy) (E) (K(ell)) (Kidd) (Lewis) (M) (N) (P) (S) (999.89)."

Although not a new note, the entry under 999.89 states "transfusion reaction NOS." Because the minor blood group reactions aren't specified under any other code, the NOS (not otherwise specified) code is the appropriate choice.

Lesson learned: The moral of this story is that using the ICD-9 book the proper way will lead you to the right code. You should always look up the condition in the alphabetic index first, then turn to the tabular list and check any detailed descriptions and "includes" or "excludes" notes to help you select the correct code.

Even if you think you know the code, starting in the alphabetic index is important -- especially when the new code manual arrives -- so you'll be sure not to miss any important changes.

Clinical importance: Separating ABO incompatibility from other minor transfusion reactions is important for health statistics, and this ICD-9 change allows better data collection.