I have been working my way through Practicode. I keep getting laterality modifiers wrong because, according to the coach, I should be going by the CMS modifiers of 0, 1, 2, 3. I have no idea how to find these and apply them. For example, there is a case of an I&D on the left lower extremity. I used the LT modifier and it was scored as incorrect. This was the answer I received from the coach. Does anyone know how to do this? Is there somewhere to enter a CPT code and find match it to this rule?
Bilateral indicators (0, 1, 2, 3) are Medicare billing rules, not from the CPT book. They show how Medicare pays for bilateral procedures:
- 0 – Bilateral rules do not apply
- 1 – Bilateral rules do apply (use modifier 50)
- 2 – Procedure is already bilateral (no modifier needed)
- 3 – Bilateral concept does not apply
Hi there - I also replied to your comment under the Practicode thread, but I’ll copy that response here as well. Normally, I’d just point you back to the other thread, but since this question really stands on its own, I think it makes sense to give it a separate thread this time.
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The laterality modifiers (RT, LT, 50) aren’t just for Medicare - they’re part of CPT coding in general. You should have seen them referenced in your CPC coursework and encountered them on the CPC exam.
Laterality is a factor when you’re coding for an anatomic structure that can be distinguished as left or right (ankles, kidneys, shoulders, lungs, breasts, etc.):
If the CPT code already defines laterality within the CPT code description, you're not typically going to need a laterality modifier.
If the CPT code does not specify laterality, and the procedure involves a left/right structure, then you'll typically need a laterality modifier to paint the full picture.
Example:
- CPT 27786 – Closed treatment of distal fibular fracture (lateral malleolus); without manipulation.
The CPT description doesn’t specify left or right, so you’d add LT or RT to show which ankle was being treated.
The Medicare Physician Fee Schedule (MPFS) can help while you’re learning laterality modifiers. The bilateral indicators (0, 1, 2, 3) tell you whether a service can be reported bilaterally or unilaterally, which can help you discern whether laterality applies to a code:
- CPT 27786 has a bilateral indicator of 1: laterality applies (right, left, or both sides).
- CPT 21337 (Closed treatment of nasal septal fracture) has a bilateral indicator of 0: no laterality applies, because the septum is a single structure.
This Novitas fact sheet helps explain a little more in plain language what the Bilateral indicators represent:
https://www.novitas-solutions.com/webcenter/portal/MedicareJL/pagebyid?contentId=00150901
As you get more comfortable over time, you probably won't have to cross-reference the MPFS bilateral indicators very often, but it can be a helpful tool now when someone is unsure when laterality modifiers are needed. (I'm not sure the context of the question you sent to the coach, but that's probably why they suggested referencing it.)