ICD-10 seeks to add greater detail to how a patient's diseases and conditions are coded. A broken arm is coded in ICD-9 as "a fractured arm," whereas in ICD-10, the injury could be coded as "a fracture of the left forearm."

Increased specificity has clear merits; Perhaps a patient no longer needs to repeat to many providers over a lifetime that it was the left arm that was fractured. As patients grow older, it's important that the details of their medical histories are stored somewhere other than in memory.

[Related: AMA adds new wrinkle to ICD-10 delay: ICD-11.]

But what are the negative implications of ICD-10's greatly expanded codeset?

Patrice Morin-Spatz, CPC, CMSCS, a certified coder through the American Academy of Professional Coders and Professional Association for Healthcare Coding Specialists, is concerned for both the provider and the patient regarding the impending ICD-10 transition. "There are ramifications using any coding system," Morin-Spatz explains. "While people think that ICD-10 will be better, they must also recognize that there will be downsides to it."

Here are nine ways Morin-Spatz believes ICD-10 could hurt providers and patients.

[See also: 5 potential ICD-10 related financial issues.]

Impact on providers

1. Updating legacy computer systems. Morin-Spatz says the computer systems at many offices, including hospitals and outpatient facilities, would need to be either updated from ICD-9 or changed entirely. Service providers will charge for the necessary upgrades.

2. New certification criteria. Current medical coders will need to retake certification exams within their professional organizations. The seminars and classes they're being asked to attend are costly, as is taking the exam itself.

3. Reformatted billing. Morin-Spatz says any doctors currently use superbills - in-house forms that are pre-printed with services and diagnoses. Physicians use these to communicate what type of office visit occurred. All of these bills will need to be reprinted, says Morin-Spatz.

4. Dual-entry procedures during transition period. For the first year or so, physicians will need to buy and use both the ICD-9 and ICD-10 books, as there will undoubtedly be a transition period when claims filed before a certain date will use the ICD-9 codes and claims filed after that date will use the ICD-10 codes.

5. Loss of productivity. Morin-Spatz notes that in countries where ICD-10 has already been implemented, there was a sizable reduction in productivity resulting in the loss of hundreds of thousands of dollars as staff got used to the new system and were, as a result, slower in processing the claims.

[See also: 5 practical tips for an easy ICD-10 transition.]

This cost companies and offices lost revenues in interest income and an attrition rate amongst employees who "threw in their towels," not wanting to learn another coding system. Human resources had to find additional personnel who may or may not have been familiar with the inner workings of the organization, resulting in more lost revenue for the groups, she says.

Impact on patients

1. Inaccurate diagnoses resulting from test ordering. Morin-Spatz gives an example of a patient who regularly visits a gynecology practice and has signs and symptoms similar to someone diagnosed with ovarian cysts. Should the physician "mark" the specific ICD-10 code for ovarian cysts before actually running any tests, the patient could have the diagnosis with her for the rest of her life, even if, after testing, no cysts were found.

2. Increased specificity could lead to increased reliance on erroneous data. If a medical coder miscodes the removal of a left lung lobe, when in fact the patient had the right lobe removed, future care providers run the risk of relying on the original, erroneous coding. What happens to that patient when, at some future date, it is the left lung that also needs to be removed? The insurance carrier may deny the claim citing that the service was "already done," Morin-Spatz notes.

3. Denial of benefits resulting from inaccurate coding. If even one digit in a code is transposed, leading to a different diagnosis than what the patient really has, Morin-Spatz says the patient may be denied life or additional health insurance because of a condition or disease they don't actually have.

4. Diagnosis codes must match treatment codes to guarantee insurance coverage. Insurance carriers can determine whether or not an indicated treatment should be reimbursed not based upon the consensus of the doctors treating the patient, but rather on whether or not she had a specific diagnosis code that would indicate additional disease, says Morin-Spatz.

[See also: 5 keys to a positive financial impact of ICD-10.]