These were completely foreign to me so I 'googled' it. Here's what I got: ICD = International Classification of Disease. It is a numerical coding system to identify, classify and monitor health conditions.
"ICD-9-CM codes are currently the cornerstone of classifying diseases, injuries, health encounters and inpatient procedures in morbidity settings. U.S. public health officials at the federal, state, and local level rely on the receipt of ICD-9-CM coded data from HIPAA-covered entities to conduct many disease-related activities. CDC programs use ICD-9-CM codes to conduct surveillance (e.g., chronic disease and injury surveillance, health care utilization, health care-associated adverse events), for case findings lists to identify cases of reportable cancers and certain birth defects and disabilities, and to provide public use data files for public analysis. A few programs abstract information from patient medical records and assign codes, and one CDC program uses ICD-9-CM codes for claims reimbursement."
ICD-10 promises to be an enhanced version.