The current standard for anemia screening, complete blood count, presents invasiveness, infrastructure requirements and high costs, leading to serious underestimation of anemia prevalence and insufficient care for anemia patients. Here, the investigators established and validated an artificial intelligence system to achieve automatic detection of anemia based on patient-sourced images of fingernails and conjunctivae. This system has been integrated into a smartphone app to be further validated through hospital-based and population-based clinical trials.

Inclusion Criteria:

• Patients should be aware of the contents and signed for the informed consent.

Exclusion Criteria:

• Patients who underwent ophthalmic or fingernail surgery in the past 30 days