TestUtah samples evaluated at Timpanogos Regional Hospital (Timpanogos) in April showed a lower rate of positives for COVID-19 than the state average. Using statistical analysis of TestUtah’s data since the beginning of April, we analyzed the hypotheses that 1) differences were due to rates of positives within the populations recruited from an online assessment versus those who were referred by a healthcare provider and 2) differences were due to laboratory and test-specific processes at Timpanogos. Changes made by the Department of Health (DOH) in the online assessment to recruit people under a similar definition of “symptomatic” used during office visits to health-care providers in the state resulted in a three-fold increase in rate of positives that was statistically indifferentiable from the statewide rate of positives for the same time period (P = 0.78). Further, the Timpanogos lab had a significantly higher rate of positives than a Utah-based national reference laboratory for the TestUtah samples (P = 0.000006). Taken together, these results highly suggest population differences stemming from a more lenient definition of who qualifies to be tested in the online assessment are responsible for the difference in rates of positives in the past. Using the Department of Health’s standard for who qualifies to be tested, TestUtah results are statistically indifferentiable from statewide averages.
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