The right arm represents a positive reaction to PPD (a skin test for tuberculosis protein). The left arm represents a positive reaction to Candida protein. Candida antigen is tested to determine if the individual's immune system is functioning well; a normal immune system demonstrates a positive reaction.
Review Date 4/17/2022
Updated by: Stuart I. Henochowicz, MD, FACP, Clinical Professor of Medicine, Division of Allergy, Immunology, and Rheumatology, Georgetown University Medical School, Washington, DC. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.