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Coding Tips: Laterality in ICD-10 Codes

Coding Tips: Laterality in ICD-10 Codes

A December 2021 communication from Anthem reminded providers that “claims processed on or after October 1, 2021, will be denied when ICD-10-CM laterality coding guidelines are not followed.” Specifically, the payer indicated that they would be monitoring diagnoses that cover diseases of the musculoskeletal system and connective tissue. Other payers also may target for denial any codes that lack specificity when it comes to laterality.

In this post, we’ll review ICD-10-CM laterality coding guidelines and offer a few recommendations.

What Is Laterality

Laterality simply identifies which side of the body a patient’s condition is on. It’s especially important for conditions that affect parts of the body that come in twos, like ears or knees or shoulders, for instance. 

Laterality usually is indicated as the fifth or sixth character, depending on the ICD-10 code, with one of the following:

  • Right side = character 1;
  • Left side = character 2;
  • Bilateral = character 3;
  • Unspecified side/region = character 0 or 9 (depending on whether it is a 5th or 6th character).

If a code requires laterality, it must be included in order for the code to be valid, even if it’s “unspecified.”

Tips for Coding Laterality

1. Determine which, if any, laterality options each diagnosis code has. Some codes have left and right options, but not bilateral. Some codes do not have laterality options at all. If a condition affects one or both sides, determine how specific you need to be in your code selection.

2. Be as specific as possible. For instance, if a code has left, right, and bilateral options, and the condition is bilateral, then you should report the code with the bilateral option. Do not report the code twice (once for left, once for right).

Or if the code does not have bilateral options, and the condition is bilateral, then you would report the code twice with left indicated in one, and right indicated in the other.

Likewise, if a code does not have laterality options at all, you would report the code only once, whether the condition is bilateral or not. Use other factors to include as much specificity as possible in your code selection.

3. Be sure diagnosis and procedure laterality match. If you have a left-side condition, for instance, be sure to include modifier LT to indicate the procedure was performed on the left side. An ICD-10 code indicating a left-side diagnosis submitted with a CPT-4 code indicating a right-sided procedure will trigger a denial, as in the following example:

  • DIAG1: H60.332 (Swimmer’s ear, left ear)
  • CPT: 69000 (Drainage external ear, abscess or hematoma; simple) MOD: RT

4. Avoid coding “unspecified,” if at all possible. While codes with laterality options often include an unspecified option, most payers will deny codes when laterality is not specified. If the medical record does not offer that information, the coder should query the patient’s provider to have the information about laterality added to the medical record via an addendum. Never guess which side was affected, nor should you code laterality based on verbal confirmation alone. 

According to the Centers for Medicare and Medicaid Services’ (CMS) ICD-10-CM Official Guidelines for Coding and Reporting, laterality can also be determined based on “medical record documentation from other clinicians,” when “laterality is not documented by the patient’s provider.” However, conflicting medical record documentation should also prompt a query to the patient’s provider.

In general, “codes for ‘unspecified’ side should rarely be used,” CMS says, “such as when the documentation in the record is insufficient to determine the affected side and it is not possible to obtain clarification.”

History of Coding Laterality

The specificity of laterality was actually highlighted as one of the benefits of ICD-10 when it was first being implemented, though it also presented a higher burden for documentation than some providers were used to. As a result, CMS implemented a 12-month grace period, during which claims would not be denied for failing to include the most specific laterality, according to Pat Maccariella-Hafey, RHIA, CDIP, CCS, CCS-P, CIRCC, Executive Director Of Education for Health Information Associates. That grace period expired on October 1, 2016, and some payers began denying claims that contained unspecified laterality. 

In fact, unspecified laterality continues to be an issue in claims processing. In addition to the reminder from Anthem mentioned above, CMS implemented a new code edit for ‘‘unspecified’’ codes in the 2022 Medicare Hospital Inpatient Prospective Payment Systems.

The code edit includes the following language: “Unspecified codes exist in the ICD–10–CM classification for circumstances when documentation in the medical record does not provide the level of detail needed to support reporting a more specific code. However, in the inpatient setting, there should generally be very limited and rare circumstances for which the laterality (right, left, bilateral) of a condition is unable to be documented and reported.”

For now, the edit will not affect the severity level of the unspecified diagnosis codes or the payment the provider is eligible to receive, though that is expected to change as the edit is phased in. 

Learn More

For more information on laterality, check out Healthcare Training Leader’s blog post: Laterality Frequently Unlocks ICD-10-CM Code Accuracy. You can also review the ICD-10-CM Official Guidelines for Coding and Reporting, approved by the four organizations that make up the Cooperating Parties for the ICD-10-CM: the American Hospital Association (AHA), the American Health Information Management Association (AHIMA), CMS, and NCHS.

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Charity Singleton Craig

Charity Singleton Craig is a freelance writer and editor who provides communications and marketing services for CIPROMS. She is responsible for creating, editing, and managing all content, design, and interaction on the company website and social media channels in order to promote CIPROMS as a thought leader in healthcare billing and management.

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