UCHealth has tested more than 12,400 people for coronavirus antibodies in the week since the health system started offering screening to anyone in Colorado.
Of the 12,438 people tested as of Wednesday, 466 were positive for COVID-19 antibodies — a rate of 3.7%, according to a news release. The group included 2,225 people who were tested in the Colorado Springs area.
UCHealth also found a 2.3% positive rate for COVID-19 antibodies among it's staff and health care providers.
The antibody rates UCHealth found are close to national averages and indicate how many people in each group have been exposed to COVID-19, said Robert Welch, lead laboratory director for UCHealth.
The positive rates among these groups are difficult to interpret without information on why individuals chose to get tested, said Kimberly Pattison, communicable disease program manager with El Paso County Public Health.
If the residents decided to get tested because they experienced illness in the past couple months and wondered if it was COVID-19, public health would expect them to have a higher positivity rate than the general public, or even health care providers who have consistent exposure, she said. But it's too soon to draw any conclusion from antibody testing because there are so many unknowns, such as how long a person could expect to have a positive antibody test after an acute infection.
When patients test positive, it could be an indicator of some immunity, but it's unknown how much, said Dr. Robin Johnson, medical director with the county health department previously.
Other coronaviruses can trigger antibodies that provide only partial and fairly short-term immunity, she said.
UCHealth advises its patients even if they test positive for antibodies to continue practicing social distancing, wearing a mask and washing their hands.
“A positive test does not mean that a person should feel he or she is safe from COVID-19, as there is not enough known about whether antibodies protect a person,” said Dr. Richard Zane, UCHealth’s chief innovation officer and chairman and professor of emergency medicine at the University of Colorado School of Medicine.
UCHealth was expecting strong interest in the antibody testing from community members and business leaders, Welch said. Community members who want to know if they were exposed to the disease can find peace of mind through the tests, Welch said.
Business leaders have also asked UCHealth to test their employees to better understand the level of risk to their workforce as they plan to reopen, he said.
"Demand for all testing has been huge since the pandemic started," Welch said.
UCHealth started getting ready to do antibody testing in March to help meet that need and it expects to provide testing as long as the need persists, he said. UCHealth charges $100 for the test.