Pediatricians may lose money or data during the mandated conversion from the current International Classification of Diseases (ICD) to its new version, according to University of Illinois at Chicago researchers.

The study is published in Pediatrics.

The ICD codes are used in managing all aspects of health care, from insurance reimbursement to staffing decisions to supply procurement to research. Pediatricians use a variety of ICD-9 codes from many different categories, including well child care, infectious diseases, injury and genetic disorders.

The ICD-10-CM, scheduled to be fully implemented on Oct. 1 of next year, includes more than 68,000 diagnostic codes, compared to 14,000 in ICD-9-CM. The Centers for Medicare and Medicaid Services provides a conversion key, called a general equivalent mapping (GEMs) code translation system, but it's complex and often difficult to interpret. While some codes map easily to the new code, others have convoluted mappings that can be inconsistent.

Researchers have reviewed commonly used codes to predict how the transition from ICD-9-CM to ICD-10-CM will likely affect pediatricians' practices. Some studies estimate that implementation of ICD-10 will cost between $83,000 and $2 million per practice, depending on size.

The UIC researchers wanted to find out which codes could potentially cause financial or information loss if they were mapped to incorrect ICD-10 codes. They used 2010 Illinois Medicaid data to identify ICD-9-CM codes for pediatric patients treated at the University of Illinois Hospital & Health Sciences System. They identified 2,708 diagnosis codes used by pediatricians in 174,500 patient encounters for a total Medicaid payment of $12,298,520.

Using a web-based tool developed at UIC, the researchers input the ICD-9 codes and mapped them to ICD-10 codes. The codes were then categorized by the complexity of the transition - from easy to complex or convoluted - and assessed for financial impact.

Twenty-six percent of pediatric ICD-9 codes have complex mapping to ICD-10, representing 21 percent of Illinois Medicaid pediatric patient encounters and 16 percent of total reimbursements.

If pediatricians use incorrect mappings, or if insurers disagree with how examinations and procedures are coded, practices may not get reimbursed and clinical information can be lost, says Dr. Andrew Boyd, UIC assistant professor of biomedical and health information sciences and one of the study's co-authors.

For example, the ICD-9 code V38.30 "Twin, mate stillborn" maps to ICD-10 code Z38.30 "Twin liveborn."

"Many pediatric practices, perhaps more than other medical fields, practice on a narrow financial margin and are often reimbursed at lower rates than other specialties, particularly by Medicaid," said Dr. Rachel Caskey, UIC assistant professor of pediatrics and co-author of the study.

"Any discrepancies that could cause even a small decrease in reimbursement - even 5 percent - could have a substantial impact on some pediatric practices, particularly an outpatient practice with a large Medicaid population."