Code each side separately when no bilateral ICD-10-CM code is provided.

Outline (quick skeleton)

• Opening hook: Why laterality and specificity matter in ICD-10-CM coding

• Core rule explained: When there’s no bilateral code, code separately for left and right

• Why this approach earns accuracy and better reimbursement

• How to apply the rule step by step

• Real-world example: carpal tunnel syndrome (right and left vs. bilateral)

• When a bilateral code does exist: use it, but don’t force it

• Documentation tips to support the codes

• Pitfalls to avoid and a concise recap

Article: The right way to code when a bilateral code isn’t provided

Let’s start with a simple truth that trips people up in the moment: accuracy in coding isn’t just about picking a code that sounds close. It’s about capturing the exact clinical picture, including which side is affected. When a condition shows up on both sides, and there isn’t a dedicated bilateral code, the way you code tells the story of the patient’s anatomy as clearly as possible. So, what do you do? The answer is straightforward: assign separate codes for each side.

What the rule actually means

If you’re looking at the ICD-10-CM guidelines and you don’t find a specific bilateral code for a condition, you code the left side and the right side separately. Why not just tuck everything into one bilateral entry? Because sometimes the anatomy, severity, or treatment differs between the two sides, and the payer and the clinician both benefit from that granularity. Think of it like documenting two different chapters of the same story—each side has its own details that matter for treatment plans, outcomes tracking, and reimbursement.

This approach isn’t a whim. It’s about maintaining a precise clinical picture in the patient’s medical record. When the note reads “bilateral,” but there isn’t a bilateral ICD-10-CM code available for that condition, coding each side separately ensures the record reflects the real-world situation. That specificity helps the care team coordinate services and ensures that billing aligns with the actual care delivered. It’s a small difference with a big payoff.

How to apply the rule, step by step

• Step 1: Look for a bilateral code. If you find one, that’s your go-to. Use it and document that both sides are involved.

• Step 2: If no bilateral code exists, separate codes for each side. Assign the right-side code first, then the left-side code, both tied to the same condition unless the documentation indicates different subtypes or severities.

• Step 3: Double-check the documentation. The chart should clearly state which side is affected. If the note only says “bilateral” without explicit sides, you’ll often need to request clarification, or code using the available left and right codes if the patient is documented as having both sides affected.

• Step 4: Consider sequencing. If one side is the primary concern or has more severe symptoms, you may place that side’s code first, but always follow the clinical documentation and payer guidelines.

• Step 5: Review for consistency. Make sure the codes you assign line up with any stated treatment, procedures, or imaging results in the note.

A concrete example you can actually picture

Let’s talk about carpal tunnel syndrome, a classic bilateral condition that shows up in many notes. Carpal tunnel syndrome has specific ICD-10-CM codes for each scenario:

• G56.01: Carpal tunnel syndrome, right upper limb

• G56.02: Carpal tunnel syndrome, left upper limb

• G56.03: Carpal tunnel syndrome, bilateral

Here’s how you apply the rule:

• If the chart explicitly states both hands are affected and there isn’t a documented bilateral code, you’d code G56.01 for the right hand and G56.02 for the left hand.

• If the note says the condition affects both hands and there is a G56.03 bilateral code listed in your coding reference, you would use G56.03 instead of two separate codes.

• If the chart only identifies one side or one symptom a day, you would code that side and document the discrepancy clearly.

This isn’t just pedantry; it’s about getting paid correctly and painting a complete clinical picture. When payers can see that you’ve captured both sides, they’re better equipped to understand the patient’s needs and the resources required. It’s a practical version of telling the full story, not just a shorthand version.

When a bilateral code does exist, use it—and don’t force separate codes

There are times when a unilateral code on each side isn’t necessary because a bilateral code is provided (like G56.03 in the carpal tunnel example). In those cases, using the bilateral code is appropriate and preferred. The key is to follow what the code set offers. If a bilateral code exists, you don’t strip it out in favor of two separate entries just because you can. Use the bilateral code when it accurately reflects the patient’s condition. Then rely on the chart to confirm that both sides are indeed involved.

Documentation tips that keep you on track

• Explicit laterality matters: It isn’t enough to say “carpal tunnel” in the note. The side(s) affected must be clear—right, left, or both.

• Use precise language: If the clinician documents “bilateral,” and you’re using a bilateral code, make sure the note supports that conclusion.

• When in doubt, flag it for clarification: A brief query to the clinician can prevent mismatches between the record and the billing.

• Cross-check imaging and procedures: If imaging shows involvement on both sides, and the codes don’t include a bilateral option, you’ll likely code separately. If it does, you’ll use the bilateral code accordingly.

• Keep payer expectations in mind: Some payers place a premium on specificity and symmetry between the clinical notes and the submitted codes. Clear documentation helps avoid denials and resubmissions.

Common pitfalls to avoid

• Jumping to the bilateral code without evidence: If the chart doesn’t document both sides, don’t assume bilateral involvement just because it seems logical.

• Reusing a bilateral code for both sides by habit: If a bilateral code exists but the condition isn’t truly bilateral, you risk a documentation and coding mismatch.

• Overlooking laterality in notes: Sometimes the laterality is buried in a routine line. Don’t skim past it—late specificity can break the chain of accurate coding.

• Mixing up sides: It’s easy to transpose right and left in a hurry. Double-check each code against the side it represents.

A quick recap you can keep in your pocket

• If there isn’t a bilateral code for a condition, code the left side and right side separately.

• Use a bilateral code when one exists and the chart confirms bilateral involvement.

• Document clearly: laterality matters, and good notes save you from back-and-forth with payers or clinicians.

• When in doubt, ask for clarification. It’s a small step that avoids big headaches later.

A note on your broader coding toolkit

This rule fits into a larger framework of specificity and accuracy in ICD-10-CM coding. It’s not a one-off trick; it’s part of the discipline of capturing the patient’s clinical journey with precision. The moment you learn to look for bilateral codes and know when to apply them versus when to code sides separately, you gain a reliable rhythm in your work. And that rhythm isn’t just about getting things right—it’s about communicating clearly with the healthcare team, ensuring the patient’s care is well-documented, and supporting fair reimbursement.

If you’ve ever juggled notes, codes, and the occasional “is this bilateral or not?” moment, you know the feeling: a tiny detail can shift the whole record. The good news is that with the guideline in hand, you have a reliable compass. When no bilateral code is provided, code left and right separately. When a bilateral code exists and the chart supports it, use the bilateral code. And always, always keep the documentation crisp and explicit about which side is affected.

So next time you’re faced with a bilateral condition, take a breath, check the codes, verify the laterality, and choose the path that gives you the most accurate, complete picture. It’s a small step, but it makes the record—and the patient—stronger.