The OASIS has changed over the years and the case mix coding guidelines have changed with it. If you struggle with knowing when to report a numeric code on M1024, Lisa Selman-Holman, JD, BSN, RN, HCSD, COS-C, consultant and principal of Selman-Holman & Associates and CoDR -- Coding Done Right in Denton, Texas offers some advice. Complete M1024 when: 1: The principal diagnosis (M1020) is a V code; the V code displaces a numeric diagnosis that is a case mix diagnosis; and the numeric case mix diagnosis is contained within one of the following three home health PPS diagnosis groups: 2: A V code in M1020 or M1022 replaces a case mix diagnosis that is a resolved condition. 3: The V code in M1020 or M1022 replaces a fracture code. Case mix controversy: In the most recent OASIS guidelines, the Centers for Medicare & Medicaid Services (CMS) instructs coders to check to see if a diagnosis will provide case mix points before placing it in M1024. However, this instruction only occurs in the case scenarios and isn't referenced anywhere else in the body of the document, notes Selman-Holman. On the other hand: CMS does state several times that it's not appropriate to select diagnosis codes based on the case mix points they may earn, Selman-Holman says. Under the current risk adjustment tables, fractures provide good risk adjustment, she says. And CMS does mention that acute fractures cannot be coded in M1020 or M1022 but can be coded in M1024. For these reasons, Selman-Holman advocates listing acute fracture codes in M1024 when the V code in M1020 or M1022 replaces a fracture code, regardless off whether you are eligible for case mix points. Tip: There is no penalty for using M1024 in other situations, as long as the diagnosis you report in M1024 is the underlying diagnosis to the V code.