Don't lose sight of the basics while you're busy with PPS changes -- your intermediary is ready to pounce on OASIS errors. Two of the top three reasons intermediary Associated Hospital Services gave for de-nials in a recent probe were that the primary diagnosis listed was not the main focus of home care and that documentation did not validate OASIS responses. Results were similar across psychiatric, hypertension and cerebral vascular disease diagnosis groups, AHS says. Protect Yourself: Focus on making sure your clinicians know that the primary diagnosis must be the chief reason for providing home care, AHS instructs. Ask which condition is most relevant to the current plan of care, is the most acute and requires the most skilled services, the intermediary says. Clinical documentation must support the OASIS answers throughout the episode, experts say. And one OASIS answer must not contradict another. Example: If you say in M0420 that the patient has pain interfering with activity daily, but not constantly, the record should show pain medication, adjustment of meds, documentation of what activities are a problem for the patient and responses to the plan of care. Note: The AHS probe information is at http://www.ahsmedicare.com/files/documents/ngs_121107home.htm.