Tumor markers
CA-125
Mucin-16 epitope; ovarian cancer surveillance, NOT a screening test.
Sample
Serum
Clinical reference range
— to 35 U/mL
Pre-/postmenopausal
Conv: —–35 U/mL
Biology
What it measures
Glycoprotein expressed on coelomic epithelium. Elevated in any peritoneal/pleural irritation.
Clinical use
Why we order it
Risk stratification of pelvic mass (use ROMA/RMI with HE4 + menopausal status). Treatment monitoring.
Differential
Causes of abnormal values
Causes of HIGH
- ↑Ovarian cancer (esp. serous)
- ↑Endometriosis
- ↑Menstruation
- ↑Pregnancy
- ↑Cirrhosis with ascites
- ↑PID
- ↑Heart failure
- ↑Pleural effusion
Pitfalls
Pre-analytic & interpretation traps
- !Useless for screening in average-risk women — too many benign causes.
- !Mucinous ovarian cancers may not produce CA-125; use CA 19-9 and CEA.