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Crosswalking ICD-9 to ICD-10 Coding is Not Easy

February 4, 2013

crosswalking ICD-9 to ICD-10While ICD-9-CM and ICD-10-CM share many similarities, the two coding systems are not identical. It is not a simple matter of swapping out a three-character code for a seven character. Medical billing is already a complex and specialized task. ICD-10 billing is going to increase the complexity of choosing a perfect diagnosis code out of a selection of approximately 13,000 possibilities to selecting an ideal diagnosis code out of 68,000 options. There is a challenge ahead for physicians, coders and medical billers starting on October 1, 2014.

It is not that ICD-9 codes cannot be crosswalked to ICD-10 codes, it’s just the result is usually inaccurate. ICD-10-CM codes are designed to communicate the maximum amount of medical information in their reported characters. The amount of data packed into an ICD-10-CM code assigned to its greatest level of specificity does not contain the same granularity that its corresponding ICD-9-CM code does. 

The Center for Medicare and Medicaid Services (CMS), which is charged with managing the final publication of ICD-10 codes, refers to crosswalking ICD-9 to ICD-10 “General Equivalence Mapping (GEM).” This is because very few ICD-9 codes have exact equivalents in ICD-10, and vice versa. Any crosswalk from an ICD-9 code only leads in the general direction of the applicable ICD-10 code. ICD-10 includes more detail abstracted from the medical record. No responsible person would crosswalk an ICD-9 code to its unspecified corollary, but it is expected many people will do just that when the ICD-10 transition takes place.

The person applying the codes needs to be aware of the differences between the two coding methodologies. Whether it is the physician, a certified professional coder, a medical documentation specialist, or a professional medical biller, a thorough understanding of the difference between the two coding systems needs to be applied for services provided after 10/01/14. Preparing beforehand, as the staff of M-Scribe Technologies is doing, will ensure that clean healthcare claims will be submitted, no matter what coding system is used.

Under ICD-9 coding, Emphysema is described by 492, with a subset of two codes to specify the patient’s chief complaint. They are: 492.0, Emphysematous bleb, and 492.8, Other emphysema. 

One popular crosswalk program directs coders to code either condition as J43.9, Emphysema, unspecified, as an acceptable alternative. Using general crosswalk software will not result in clean claims. In fact, Emphysema is described by ICD-10-CM as being J43, with a number of subset codes, ranging between J43.0 and J43.9. Where ICD-9 utilizes two codes to specify a patient’s emphysema, ICD-10 uses five. A clean healthcare claim will describe a patient’s emphysema as unilateral, panlobular, cetnrilolobular, other or unspecified. If applicable, concurrent or different codes will need to be used based on the patient’s history and presentation. The medical record should contain the required information to accurately describe the patient’s condition in the codes found in ICD-10-CM, but it can’t be done without prior mastery of the concepts used in ICD-10.

There is going to be a paradigm shift on how diagnosis information is communicated between a healthcare provider and third-party payers. Very few ICD-9 codes are exactly matched by the language and methodology of ICD-10. Auditors will read the medical record differently. If the documentation supports a more specific code, payments may be denied or recouped by payers based on the bills submitted. 

There is no substitute for professional skill. Professional medical coders and billers know how to use the available software, but they also know when the easy answer isn’t enough. By preparing now, coders and billers at M-Scribe Billing Service are ready to make the transition from ICD-9 to ICD-10 now. They can use code books without relying on algorithms and review superbills and medical records, resulting in submission of a clean claim. They are equipped now and ready for the transition, saving outpatient medical practices valuable time and resources catching up with changes in the industry.


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