Blood tests are taken to measure the levels of tumor markers. Tumor markers are substances often found in higher-than-normal amounts when cancer is present. Tumor markers may indicate the presence of a tumor even if it is too small to be detected by physical exams or imaging tests.

The following three tumor markers are used in staging testicular cancer:

• Alpha-Fetoprotein: A protein normally produced by a fetus. AFP levels are usually undetectable in the blood of healthy adult men or women (who are not pregnant). An elevated level of AFP suggests the presence of either a primary liver cancer or germ cell tumor. Also called AFP.
• Human Chorionic Gonadotropin: A hormone normally found in the blood and urine during pregnancy. It may also be produced by some tumor cells. An increased level of beta-human chorionic gonadotropin may be a sign of cancer of the testis, uterus, ovary, liver, stomach, pancreas, or lung. Beta-human chorionic gonadotropin may also be produced in response to certain conditions that are not cancer. Beta-human chorionic gonadotropin is being studied in the treatment of Kaposi sarcoma. Also called ß-hCG or HCG.
• Lactase Dehydrogenase: One of a group of enzymes found in the blood and other body tissues and involved in energy production in cells. An increased amount of lactate dehydrogenase in the blood may be a sign of tissue damage and some types of cancer or other diseases. Also called lactic acid dehydrogenase and LDH.

Tumor marker levels are measured again, after radical inguinal orchiectomy and biopsy, in order to determine the stage of the cancer. This helps to show if all of the cancer has been removed or if more treatment is needed. Tumor marker levels are also measured during follow-up as a way of checking if the cancer has come back.