OASIS Alert

If you don't understand case mix points, you should - they can add more than $5,000 in reimbursement to one home health episode.

OASIS is key for determining an episode's case mix classification, and incorrect answers can lead to inadequate payment, warns Lake Barrington, IL-based consultant Beth Carpenter with Beth Carpenter & Associates.

OASIS errors also can trigger medical review and increase an agency's risk for fraud accusations, experts say. And your agency's case mix results are used in Home Health Compare calculations to risk adjust the data for public comparison of patient outcomes between agencies.

With all the changes involving V and E codes, and all the worry about how to use M0245 for the case mix diagnosis code, it may seem that diagnosis codes are the only important part of the case mix process. But case mix involves lots more than just the diagnosis.

To determine the patient's case mix, first complete the OASIS assessment. Then take the answers to all the M0 questions involved in case mix (see chart, this issue) and add the points.

The results reflect the patient's clinical, functional and resource utilization severity, as represented by CxFxSx. For example, a patient with one of the orthopedic case mix diagnoses, some functional limitations and the need for 10 or more therapy visits might score C1F2S3.

With four clinical severity levels, five functional severity levels and four service utilization severity levels, there are 80 possible combinations in the case-mix system. All the patients whose scores place them in the same set of severity levels for the three dimensions - such as all who score moderate clinical, minimal functional and low service utilization - would be in the same group.

Using a standard base rate of $2,230.65 for fiscal year 2004, different case mix combinations pay very different amounts, according to Jim Robin-son, senior financial analyst with Rohnert Park, CA-based Boyd & Nicholas. An episode reimburse-ment for a patient whose case mix is C0F0S0 (clinical, functional and severity levels all minimum) would be $1,174.44, while for a patient classified as C3F4S3 (the highest severity in all three) it would be $6,271.03, he illustrates. Those amounts are unadjusted for the local wage index.

Agencies aren't likely to see many C0F0S0 patients who also qualify as homebound, suggests consultant Melinda Gaboury with Nashville, TN-based Healthcare Provider Solutions. But even looking at one portion of the case mix illustrates how important accuracy in assessment and documentation is to an agency's bottom line.

An agency will receive more than $1,000 extra for a patient with a clinical severity level of three (C3) than it will for a patient with a clinical severity rating of zero (C0), Gaboury says. And the reimbursement difference between service utilization levels zero (S0) and three (S3) can be more than $2,500.

Chart review is one way to determine if a patient has been inaccurately assessed and should be in a higher case mix, Gaboury suggests. Designate a person in your agency to look at the home health resource groups and HIPPS codes to make sure that the coding makes sense, she adds.