Three-year-old labrador retriever Tess has used her outstanding nose hundreds of times since last year to detect the scent of COVID-19 in human sweat samples.

Now, after completing her training with flying colors, she’s helping to screen surgery patients a week prior to their procedures at The Queen’s Medical Center in Honolulu as part of an ongoing study conducted by the Maui nonprofit Assistance Dogs of Hawaii in partnership with the hospital.

So far, she has shown a knack for finding any whiff of the coronavirus. Tess has accurately identified nearly all of the 369 COVID-19 negative samples and 146 positive samples presented to her since the project began in November, said Maureen Maurer, trainer and the nonprofit’s executive director.

Tess is one of four dogs trained by the Maui nonprofit, which will present its findings for peer review in a medical journal later this month and offer a Hawaii contribution to a larger body of international research spearheaded by the London School of Hygiene and Tropical Medicine, Maurer said Thursday at a press conference.

Of the 86 patient samples Tess has inspected during the past two weeks at Queen’s, she’s accurately ruled out a COVID-19 diagnosis for all of them, Maurer said. Those results are confirmed by follow up molecular testing, and a positive COVID-19 sample is always planted at random to ensure accuracy.

“Tess’ results come back before the (molecular) PCR test,” she said. “I like to call it the other lab test.”

Maurer hopes to scale the training program by sharing it with other agencies and having dogs provide additional COVID-19 screening at airports, hospitals, assisted living centers and schools. Dogs can screen as many to 200 to 300 people per day in the same environment, Maurer said.

“It’s just a very accurate, efficient and inexpensive way to screen large numbers of people,” she said. “We’ve met with state and county officials who have expressed interest in this research and possibly implementing it in different areas.”

Together, the four dogs trained by Assistance Dogs of Hawaii have accurately identified nearly 100% of positive samples. Their specificity rate, or rate at which they correctly ignore negative samples, was an average of 90%.

“Dogs are extremely accurate at identifying COVID-19 and there have been very few cases of false positives,” said Maurer, who has trained dogs in the past to detect bacterial infections. “They won’t take the place of PCR tests but they can accurately and efficiently read hundreds of people per day.”

Dogs’ ability to detect the virus that causes COVID-19 in various bodily fluids, including saliva, sweat and urine, is being tested across the globe. The World Health Organization published a blueprint on the topic in March.

“There is already a large body of evidence that dogs are able to detect SARS-CoV2 infected cases from various body fluids, as they are for other both infectious and noninfectious diseases,” according to the WHO report. “Dogs could potentially complement currently available diagnostic tools and approaches for COVID-19 but also other pathologies and provide new applications for public health.”

Dogs are also quick learners, Maurer said, and can be trained within a matter of weeks, although it’s not yet known what molecule the dogs are identifying in the COVID-19-positive sweat samples on cotton swabs.

Also unanswered is how soon into a viral infection the dogs are able to detect COVID-19. Maurer hopes to answer that by recruiting more Hawaii volunteers, especially those who believe they have been exposed to COVID-19, such as family members of people who have already received positive molecular-based test results.

The findings, while preliminary, are promising to the medical community, said Dr. Whitney Limm, executive vice president of clinical integration at The Queen’s Health Systems.

Limm and Maurer are discussing more ways the dogs can help on the hospital campus. If a dog detects the COVID-19 virus in someone, medical personnel will follow up with a rapid test, he said.

“This offers an opportunity for a non-invasive testing, adding a layer of security without doing something intrusive. It’s just an added layer of comfort that brings actual joy to people who see the dogs,” he said.

Civil Beat’s coverage of Maui County is supported in part by a grant from the Nuestro Futuro Foundation.