Different tracking methods of Idaho's coronavirus testing have led to varying reports of the state's positivity rate.
As the Idaho Press reported Friday, John Hopkins University estimates Idaho has a 23% positivity rate, while the state's estimate is closer to 10.5%. That's because each are using a different method for calculating the rate.
John Hopkins factors in the number of COVID-19 cases in its calculation, while the state looks solely at positive and negative tests.
"The reporting mechanisms in place in our country are not perfect,” Central District Health spokesman Brandon Atkins said. "… If the metrics and data were being displayed uniformly, it would certainly help.”
The university said the ideal method would be to divide the number of positive tests by the number of people tested, but it doesn't go that route because not every state makes complete testing data available. The university's calculation, applied uniformly nationwide, shows Idaho with the second-highest positivity rate.
Idaho Health and Welfare officials reach the state's calculation by dividing the number of positive tests by total tests. However, some test results aren't factored in. That's because laboratories are only required to report positive tests to the state, not negative tests. Positive test results from labs that don't also report negative tests aren't included in the state's estimate.
The number of labs that don't provide negative test results is a small one, according to the Department of Health and Welfare.
“There are currently 67 laboratories and healthcare organizations that are sending us both positive and negative results on a regular basis,” a department statement reads. “The number of organizations not sending negative results can vary week to week and are usually smaller clinics or out of state hospitals that might treat an Idaho resident. That number is 15-20.”
When looking at positivity rates, Atkins said, "States and local jurisdictions have a better grasp on localized data and work to provide results that reflect the granular work they are doing. The further away from the picture, the more challenging it is to see the details."
Still, a more uniform tracking method would be helpful, he noted.
“If we had a uniform testing system that met reporting requirement 100% of the time for all tests … and this data was made seamlessly accessible to all reporting sources, we might get a step closer," Atkins said. "It has never been the case and I fear will elude us indefinitely.