Section 412.10 - Changes in the DRG classification system(a)General rule. CMS issues changes in the DRG classification system in a FEDERAL REGISTER notice at least annually. Except as specified in paragraphs (c) and (d) of this section, the DRG changes are effective prospectively with discharges occurring on or after the same date the payment rates are effective.(b)Basis for changes in the DRG classification system. All changes in the DRG classification system are made using the principles established for the DRG system. This means that cases are classified so each DRG is-(1) Clinically coherent; and(2) Embraces an acceptable range of resource consumption.(c)Interim coverage changes - (1)Criteria. CMS makes interim changes to the DRG classification system during the Federal fiscal year to incorporate items and services newly covered under Medicare.(2)Implementation and effective date. CMS issues interim coverage changes through its administrative issuance system and makes the change effective as soon as is administratively feasible.(3)Publication for comment. CMS publishes any change made under paragraph (c)(1) of this section in the next annual notice of changes to the DRG classification system published in accordance with paragraph (a) of this section.(d)Interim changes to correct omissions and inequities - (1)Criteria. CMS makes interim changes to the DRG classification system to correct a serious omission or inequity in the system only if failure to make the changes would have- (i) A potentially substantial adverse impact on the health and safety of beneficiaries; or(ii) A significant and unwarranted fiscal impact on hospitals or the Medicare program.(2)Publication and effective date. CMS publishes these changes in the FEDERAL REGISTER in a final notice with comment period with a prospective effective date. The change is also published for public information in the next annual notice of changes to the DRG classification system published in accordance with paragraph (a) of this section.(e)Review by ProPAC. Changes published annually in accordance with paragraph (a) of this section are subject to review and comment by ProPAC upon publication. Interim changes to the DRG classification system that are made in accordance with paragraphs (c) and (d) of this section are subject to review by ProPAC before implementation.50 FR 35688, Sept. 3, 1985, as amended at 51 FR 31496, Sept. 3, 1986; 57 FR 39820, Sept. 1, 1992