LOS ANGELES -- U.S. researchers have developed an AI-augmented smartphone app capable of noninvasively estimating blood hemoglobin levels and screening for anemia based on photos of users' fingernails, according to a new study published Tuesday in Proceedings of the National Academy of Sciences (PNAS).

The app demonstrated high accuracy when compared to self-reported complete blood count results from 9,061 users. Over 1.4 million uses of the app also enabled the creation of a real-time anemia prevalence map across the United States, the study noted.

Researchers said the noninvasive and easily accessible nature of the tool makes it a promising solution for large-scale anemia screening and monitoring, particularly in low-resource settings.

They also highlighted the app's potential for personalized health tracking, allowing individuals with anemia to monitor their own hemoglobin levels over time.