The difference is in the documentation, so you may need to ask for it.
Good coding practice is to get as much detailed documentation about a patient as possible. And that’s even more important under PDGM.
According to available documentation, about 70% of the top 75 codes currently used as primary diagnoses are invalid as primary diagnoses under PDGM. The reason? They are classified as “too vague” to justify being the primary reason for a home health plan of care. In other words, these codes raise questions about whether your agency has a legitimate reason to bill Medicare for reimbursement of its services.
If, for instance, you code for a patient with pain in her right knee using code M25.561 (Pain in right knee) as the primary diagnosis, your claim will come back, without payment, with a request for re-coding.
You shouldn’t code M25.561 per the coding guidelines under the current payment system if you have a known underlying diagnosis, so this isn’t a new concept. However, these “too vague” codes are completely invalid under PDGM — they just won’t be accepted.
If you know that that the source of a patient’s right knee pain is primary osteoarthritis in that joint, you would code M17.11 (Unilateral primary osteoarthritis, right knee) as primary. This code would not cause the claim to be sent back.
Note: As usual, the details for diagnosis codes come from the physician and they better enable you to code accurately. If you don’t have the information you need in the patient’s record, you should expect to query the physician to get it.
It may not be a favorite task, but it’s a crucial one, both in terms of patient treatment and claims reimbursement. It could save you trouble now, and it will definitely save you from an unpaid, returned claim in a post-PDGM world.