Castle Biosciences, Inc., a molecular diagnostics company, provides test solutions for the diagnosis and treatment of dermatologic cancers, Barrett’s esophagus (BE), uveal melanoma, and mental health conditions. The company offers DecisionDx-Melanoma, a risk stratification gene expression profile (GEP) test that predicts the risk of metastasis for patients with uveal melanoma; DecisionDx-SCC, a risk stratification test for cutaneous squamous cell carcinoma; MyPath Melanoma, a diagnostic GEP test for use in patients with difficult-to-diagnose melanocytic lesions; and TissueCypher, a risk stratification spatial-omics test to predict future development of progression of high-grade dysplasia and/or esophageal cancer in patients with non-dysplastic, indefinite dysplasia, and low-grade dysplasia BE. It also provides DecisionDx-UM, a risk stratification GEP test that predicts the risk of metastasis for patients with uveal melanoma; and IDgenetix, a pharmacogenomic test that helps guide optimal drug treatment for patients diagnosed with major depressive disorder, schizophrenia, bipolar disorder, anxiety disorders, social phobia, obsessive-compulsive personality disorder, post-traumatic stress disorder, and attention deficit hyperactivity disorder. The company offers its products to skin cancer and gastroenterology markets.