Idaho’s state lab mixed up monkeypox tests. Here’s how it happened.

Two monkeypox patients received inaccurate results that later were corrected

By: - August 4, 2022 4:00 am
Monkeypox virus, illustration

At the center of each monkeypox virus is a core nucleoprotein (red) that contains the DNA (deoxyribonucleic acid) genome. This is surrounded by an outer membrane (blue) that displays surface tubules (green). This virus, which is found near rainforests in Central and West Africa, causes disease in humans and monkeys, although its natural hosts are rodents. It is capable of human-to-human transmission. In humans it causes fever, swollen glands and a rash of fluid-filled blisters. (Getty Images)

Two samples arrived last Thursday at the Idaho Bureau of Laboratories. Health care providers in two different parts of the state had swabbed their patients to test for suspected monkeypox infections.

The lab processed the monkeypox tests and sent out results.

Four days later, the state lab got a query from the Centers for Disease Control and Prevention. The CDC had received samples from the same patients, to confirm the state lab’s results — but those samples and test results didn’t match.

It turned out that Idaho’s state lab had inadvertently swapped the two patients’ samples. It wasn’t just a paperwork error, though. It caused one person who didn’t have monkeypox to get a positive result and — more concerning for public health — one person who did have monkeypox to get a negative result.

The Idaho Department of Health and Welfare announced the lab’s error, and its subsequent investigation into the error, in a news release Tuesday.

Monkeypox outbreak: status report

The CDC reports 6,617 confirmed cases of monkeypox in the U.S., as of Aug. 3.

At least six of those cases are in Idaho, according to state and local public health agencies. Idaho’s first case was confirmed nearly a month ago.

At least 500 vaccine doses have been provided to Idaho and distributed to public health districts.

More than 26,000 cases are reported worldwide, with the U.S. reporting the largest number of any country.

Christopher Ball, director of the Idaho Bureau of Laboratories, told the Capital Sun on Tuesday afternoon what went wrong and what the laboratory is doing to prevent future errors.

The laboratory is one of Idaho’s largest and most capable of running complex tests. It has been the starting place for much of the pandemic’s COVID-19 testing advancements. It also has a high-containment area, where scientists can safely run tests for things like monkeypox without contaminating the rest of the lab.

There’s an important rule for the containment area: Objects that go in do not come out. So when the laboratory received a potentially infectious sample, an employee would take the specimen into the containment area and leave the paperwork behind in the lab, so it wouldn’t have to be destroyed.

Each sample comes with two labels that identify the patient. One label stays with the paperwork; one goes with the specimen.

Before the current monkeypox outbreak, the lab rarely needed to test more than one patient’s sample a day in the containment area, Ball said, so there were few situations where labels could be mixed up between two samples.

But on Thursday, the lab received two samples, and that’s just what happened.

“We all felt pretty foolish once we saw the error of our ways,” Ball said. “How my staff handled it, as soon as they were alerted to a problem (by the CDC on Monday), they immediately notified me.”

The laboratory corrected the test results and sent them out immediately, he said. Still, a patient with monkeypox may have spent four days believing they didn’t have an infectious disease.

photos of monkeypox on finger, torso, hand
Monkeypox can appear on any body part. (NHS England High Consequence Infectious Diseases Network/CDC)

Ball said the staff quickly came up with a simple solution to prevent a problem of this magnitude in the future: make an extra copy of the paperwork that can be thrown away, so it can go into the containment area alongside the test specimen.

“Mistakes, unfortunately, are part of the laboratory business,” Ball told the Idaho Statesman in an interview about the error. “How they’re handled is the measure of the staff we have here.”

What about earlier samples? Has this ever happened before, and the CDC or the state lab just didn’t catch the error?

Ball said that was part of the investigation.

“Because we get so few samples in our high containment lab,” there weren’t many tests where a mixup was even possible, he said, but a review of those tests found “no evidence to suggest” this ever happened before.

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Audrey Dutton
Audrey Dutton

Audrey Dutton was a senior investigative reporter with the Idaho Capital Sun after 10 years at the Idaho Statesman. Her favorite topics to cover included health care, business, consumer protection issues and white collar crime. Before coming home to Idaho, Dutton worked as a journalist in Minnesota, New York, Maryland and Washington, D.C. Dutton's work has earned dozens of state, regional and national awards for investigative reporting, health care and business reporting, data visualization and more.