Though the test can't pinpoint the virus subtype or source, most of the detections are from states hard hit by H5N1 in dairy herds.
In other developments, the USDA announced a pilot bulk milk testing program as an option for farmers to monitor herd health.
Unlike similar earlier cases in the United States, the newly reported patient had respiratory symptoms.
The USDA's updated list of H5N1 detections in mammals includes domestic cats in 4 states.
In other developments, H5N1 was detected in feral cats in New Mexico and more dairy herds in affected states.
An investigation found that the woman had been exposed to backyard poultry before she became ill.
The positive sample was from 1 of 96 culled dairy cows that were tested at slaughter, and none of the meat entered the food supply.
The group also used the contaminated milk samples to examine heat treatment and refrigeration impacts.
Also today the USDA confirmed 6 more outbreaks in dairy herds and announced 5 more poultry outbreaks, all from Minnesota.
Findings underscore the risk to dairy workers and suggest that contaminated milking equipment may be partly responsible for cattle-to-cattle spread.
