New smartphone app screens for a concerning blood condition — using a photo of your fingernails

New York Post

22-05-2025

They're trying to put the 'cure' in manicure.
Researchers from Emory University and Georgia Tech developed a smartphone app to screen for anemia using images of a person's fingernail beds instead of the conventional blood test.
Anemia, which is believed to affect over 2 billion people worldwide, occurs when someone does not have enough healthy red blood cells or hemoglobin to carry oxygen to the body's tissues.
3 Iron deficiency has been called one of the world's most widespread nutritional problems.
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The color of the fingernail bed reflects the amount of hemoglobin in the blood. Hemoglobin is the protein in red blood cells that carries oxygen through the body and gives blood its signature red hue.
When hemoglobin levels drop, fingernail beds appear paler.
The AI-powered algorithm in the new app was tested on over 9,000 users, whose fingernail selfies were compared to their clinical blood test results.
Within seconds of submitting a fingernail photo, the tech estimated hemoglobin levels with remarkable accuracy.
When using a hemoglobin threshold of 12.5 g/dL to identify anemia, the app achieved 89% sensitivity and 93% specificity, numbers on par with traditional screening methods.
For those with chronic anemia, there's a 'personalization feature' in the app that can be calibrated to a user's baseline by entering lab-confirmed hemoglobin results alongside the app's estimates.
After personalization, the app's performance approached levels seen in medical devices cleared by the Food and Drug Administration for non-invasive hemoglobin measurement.
Results from this study were published this month in the Proceedings of the National Academy of Sciences.
3 The color of the fingernail bed reflects the amount of hemoglobin in the blood.
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The technology, now licensed to Sanguina, has been made publicly available for download and used more than 1.4 million times in the US.
Traditional anemia testing requires blood work, lab access, and, in most cases, insurance coverage.
The team behind the app is hopeful that it will prove revolutionary for those with chronic conditions like kidney disease, cancer or nutritional deficiencies that require regular hemoglobin monitoring.
Symptoms of anemia include fatigue, weakness, cold extremities, chest pain, pale skin, loss of appetite, shortness of breath, lightheadedness, headaches and cravings for non-nutritional objects like ice, soil, paper and even clay.
3 Researchers maintain that their new app is not intended to replace medical care but to support screening and monitoring, particularly for those with chronic anemia and those living in remote or underserved communities.
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Widespread use of the app has revealed geographic and demographic anemia patterns.
Android users, who typically spend less on their devices than iPhone users, showed lower hemoglobin levels, suggesting a link between income and anemia.
Further analysis shows that places with higher median incomes, higher percentages of black residents, larger populations and more primary care physicians per resident had more app users.
Researchers maintain that the app is not intended to replace medical care but to support screening and monitoring, particularly for those with chronic anemia and those living in remote or underserved communities.
And screening has never been more critical.
Iron deficiencies like anemia compromise the immune system, making it harder for the body to fight illness. Further, research has found that anemia is present in 30% to 75% of colorectal cancer patients.