Far from just a routine coding update, the switch from ICD-9 to ICD-10 altered the very structure of coding procedure. While such a huge change may seem like a hassle, your practice can code more precisely and get paid easier with ICD-10. Here are the biggest differences between ICD-9 and ICD-10:

ICD 10 has alphabetical codes

While ICD-9 codes exclusively include numbers, ICD-10 codes include alphabetical characters and numbers. With this increased flexibility, ICD-10 encodes many more procedures.

ICD-10 codes often look markedly different from ICD-9 codes because of this distinction:

ICD-9 code: 692.72 - Solar radiation dermatitis

ICD-10 code: 0DN90ZZ - Release of duodenum, open approach

ICD 10 codes are longer

The brevity of ICD-9 codes limited the availability of new code designations. ICD-9 codes were 3-5 characters long, ICD-10 codes can use up to 7 characters.

68,000 codes are available under ICD-10 - five times the amount available under ICD-9. With more coding space, ICD-10 adapts to changing medical practices much easier than ICD-9.

Some ICD-10 databases convert ICD-9 codes into ICD-10 for you and demonstrate the additional information that longer codes include.

ICD 10 codes are more specific

With its greater length, ICD-10 encodes greater specificity than ICD-9. These codes narrow down procedures to particular areas of a limb. The American Medical Association offers this example of specificity building:

S52 Fracture of forearm

S52.5 Fracture of lower end of radius

S52.52 Torus fracture of lower end of radius

S52.521 Torus fracture of lower end of right radius

S52.521A Torus fracture of lower end of right radius, initial encounter for closed fracture


ICD-10 includes laterality distinctions - medical staff can distinguish between right side and left side procedures. A major improvement from ICD-9, this update decreases billing confusion and denials by clarifying the exact area treated.

ICD 10 codes are more modern

ICD-9 originated in 1975 at a WHO conference as the coding standard for medical procedures. Many chapters quickly filled up, preventing the addition of new codes.

ICD-10 is an updated coding procedure for a growing industry. With over 68,000 available combinations, ICD-10 can add new codes easily.

In fact, the CDC adds new codes every year (and deletes outdated codes). New ICD-10 codes for the 2019 fiscal year, which begins October 1, 2018, were released on June 11, 2018.

ICD 10 allows combination codes

According to the ICD-10 Official Guidelines, combination codes can include two diagnoses, one diagnosis with a secondary manifestation, or a diagnosis with a related complication.

For example, ICD-9 uses two codes when a patient has both diabetes and a condition caused by diabetes, but ICD-10 combines both into one code:

ICD- 9 codes

249.50 Secondary diabetes mellitus with ophthalmic manifestations, not stated as uncontrolled, or unspecified

250.50 Diabetes with ophthalmic manifestations, type II or unspecified type, not stated as uncontrolled

ICD-10 code

E13.37X1 Other specified diabetes mellitus with diabetic macular edema, resolved following treatment, right eye

ICD-9 vs. ICD-10

ICD-10 codes offer greater specificity and more options than ICD-9 codes. While the number of codes is intimidating, ICD-10 decreases claim denials by offering more information about each procedure.

ICD-10 accepts suggestions for new codes, so if you encounter a new combination of diagnoses or think a code should be modified, you can submit a proposal to the CDC.

If you’re unsure how to code your medical procedures, consider hiring a medical billing and coding company that will save you time and headache.

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