The Centers for Medicare & Medicaid has modified its methodology used for classifying county-level COVID-19 data that determines how often nursing homes will have to test staff members for the disease. 

The American Health Care Association/National Center for Assisted Living detailed the changes following the latest county-level data update in a blog post Monday. CMS expanded the measure to include 14 days of data from counties, instead of the previous seven days, in order to use a “greater amount of data to calculate percent test positivity and improve the stability of values.”

“Further, because there are instances where counties with high test positivity rates may reflect low testing levels rather than high levels of viral transmission, additional criteria were added to re-assign counties with low testing volume to lower nursing home staff testing tiers,” CMS stated. 

For example, the agency noted that communities with low levels of testing and high test positivity, of greater than 10%, will be reassigned to either the yellow or green testing tiers. 

The agency has previously called for nursing home staff to be tested once a month if their county-level positivity rate was below 5%; once a week if the positivity rate was between 5% and 10%; and twice a week if the rate was over 10%.

It used green, yellow and red to classify the counties. Nursing homes in green counties have to test staff once per month; yellow counties must test staff once per week; and staff in red counties must be tested twice per week. 

The revised methodology now states that counties with a positivity rate of less than 5% or less than 20 tests in the past 14 days will be classified as green counties. Those with a positivity rate between 5% and 10%, or have less than 500 tests and less than 2,000 tests per 100,000 with a positivity rate of higher than 10%, will be classified as a yellow county. 

Counties that have a 10% positivity rate or higher and don’t meet the criteria for either the green or the yellow standards will be classified as a red county. 

“Test positivity is rounded to the nearest tenth of a percent before classifying,” the agency added. 

County-level data can be viewed here.

In other data-related news, a federal watchdog agency suggested that the Department of Health and Human Services could improve its COVID-19 data collection efforts for nursing homes.

The Government Accountability Office in a blog post Monday said the agency has found that HHS’s data on COVID-19 in nursing homes don’t capture early months of the pandemic. It encouraged the department to consult with CMS and the Centers for Disease Control and Prevention to “develop a strategy to capture more complete data on COVID-19 cases and deaths in nursing homes retroactively back to January 1, 2020.”