Part 4/7:
To ensure reliability, the developers collaborated with trained hematologists, comparing their assessments of fingernail color with actual blood hemoglobin levels. The results demonstrated that the app's estimates were accurate within approximately plus or minus 10% of the gold-standard complete blood count (CBC) test. This level of precision is remarkable for a non-invasive, smartphone-based method and suggests the app could serve as a screening tool capable of identifying individuals who require further testing or immediate intervention.