From the Guidelines
The primary purpose of the Human Chorionic Gonadotropin (HCG) tumor marker test is to diagnose, monitor, and check for recurrence of germ cell tumors, particularly testicular cancer in men and certain ovarian cancers in women, as well as gestational trophoblastic diseases and some rare cancers. This test is crucial in determining prognosis and assessing treatment outcome, especially when used in conjunction with other serum tumor markers like alpha-fetoprotein (AFP) and lactate dehydrogenase (LDH) 1. The HCG test involves a simple blood draw, with results typically available within a few days, and normal levels in non-pregnant adults are generally below 5 mIU/mL.
Key Points to Consider
- Elevated HCG levels may indicate the presence of cancer, while decreasing levels during treatment suggest the therapy is working 1.
- HCG can also be elevated during pregnancy, by certain medications, or by marijuana use, so these factors must be considered when interpreting results.
- The test is useful for monitoring all stages of nonseminomas and metastatic seminomas, as elevated marker levels can be an early sign of relapse 1.
- The approximate half-life of AFP is 5 to 7 days, and a non-seminoma is associated with elevated serum concentrations of AFP 1.
Clinical Application
In clinical practice, the HCG tumor marker test is an essential tool for diagnosing and monitoring germ cell tumors, and its results should be interpreted in the context of other clinical and laboratory findings 1. The HCG test should be ordered as part of a comprehensive evaluation when cancer is suspected or to monitor known cancer during and after treatment, taking into account the potential factors that can affect HCG levels, such as pregnancy, medications, or marijuana use 1.
From the Research
Purpose of Human Chorionic Gonadotropin (HCG) Tumor Marker Test
The Human Chorionic Gonadotropin (HCG) tumor marker test is used for several purposes, including:
- Detection and monitoring of pregnancy and pregnancy-related disorders 2
- Detection and monitoring of trophoblastic tumors of placental and germ cell origin 2, 3, 4, 5
- Detection and monitoring of non-trophoblastic tumors, such as biliary and pancreatic cancer 2
- Initiation of treatment for relapsing choriocarcinomas and testicular germ cell tumors based on rising HCG levels 2
Types of HCG and Their Clinical Significance
There are different types of HCG, including:
- Intact heterodimeric hormone consisting of an alpha (HCGalpha) and a beta subunit (HCGbeta) 2
- Hyperglycosylated HCG, which is an independent molecule to regular HCG and is produced by cytotrophoblast cells 4, 5
- Free beta-subunit of HCG, which is an autocrine or cytokine and is produced in most gynecologic malignancies 4
Clinical Applications of HCG Tumor Marker Test
The HCG tumor marker test has several clinical applications, including:
- Diagnosis and management of gestational trophoblastic diseases 4, 5
- Diagnosis and management of germ cell tumors of the testis and the ovary 3, 6
- Monitoring of treatment response in patients with trophoblastic and non-trophoblastic tumors 2, 3
- Early detection of new or recurrent trophoblastic disease 5