When expanded to the validation sample sets (33 normal subjects and 33 AD patients) from the community-based Ansan Geriatric Study19, the AD Litmus Gene Assay showed that the gene expression of SPC25 was significantly up-regulated (p = 0.020) in AD serum-treated cells (Fig. 2c), but not FAM55C. According to our ROC analysis, the AD Litmus Gene Assay did not show a strong power of discrimination between AD serum and normal samples, with an area under the curve of 0.663 (95% CI: 0.530–0.795, p = 0.023) (Fig. 2d). The gene discussed is SPC25; the disease is Alzheimer disease.