DefinitionCarpal tunnel biopsy is a test in which a small piece of tissue is removed from the carpal tunnel (part of the wrist).Alternative NamesBiopsy – carpal tunnelHow the test is performedThe skin of your wrist is scrubbed and injected with medicine that numbs the area. Through a small cut, a sample of tissue is removed from the carpal tunnel. This is done by direct removal of tissue or by needle aspiration.Sometimes this procedure is performed at the time of carpal tunnel release.How to prepare for the testYour doctor or nursemay ask that you not eat anything for a few hours before the test.How the test will feelYou may feel some stinging or burning when the numbing medicine is injected. You may also feel some pressure or tugging during the procedure. Afterward, the area may be tender or sore for a few days.Why the test is performedThis test is usually done to see if you have a condition called amyloidosis. It is not usually done to diagnose carpal tunnel syndrome.Normal ValuesNo abnormal tissues are found.What abnormal results meanAn abnormal result is a sign of amyloidosis.What the risks areBleedingDamage to the nerve in this areaInfection (a slight risk any time the skin is broken)Special considerationsIf the carpal tunnel biopsy reveals a problem, your health care provider may suggest a carpal tunnel release procedure. Additional surgery to correct or improve the problem may be recommended.advertisementReferencesGertz MA. Amyloidosis. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011: chap 194.LeBlanc KE, Cestia W. Carpal Tunnel Syndrome. Am Fam Physician. 2011;83(8):952-958.Review Date:8/11/2012Reviewed By:Linda J. Vorvick, MD, Medical Director and Director of Didactic Curriculum, MEDEX Northwest Division of Physician Assistant Studies, Department of Family Medicine, UW Medicine, School of Medicine, University of Washington. C. Benjamin Ma, MD, Assistant Professor, Chief, Sports Medicine and Shoulder Service, UCSF Department of Orthopaedic Surgery. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M. Health Solutions, Ebix, Inc.