Carbohydrate Antigen 125
CA125 is raised in ovarian cancer but it is also produced by
most adenocarcinomas. CA125 is a reliable marker for
monitoring epithelial carcinoma of ovary, but the specificity of
the marker is such that it should not be used as a
primary diagnostic test for ovarian carcinoma.
Evidence for use of CA125 in early detection of familial ovarian
carcinoma is limited and should be restricted to prospective
CA125 may also be used as part of pre-op assessment for
suspected ovarian malignancy, in conjunction with clinical
examination and imaging. Measurement in patients with pelvic
masses may help differentiate malignant from benign lesions, but
masses close to the ovaries may be associated with misleadsingly
high levels of this marker.
Recent evidence suggests that CA125 may be useful as a
preoperative prognostic marker for transitional cell carcinoma of
the bladder and in the follow-up of bladder cancer. This is
the only indication for carrying out this test in men.
Request on ICE
Analysed by referral laboratory if specific criteria met or
requested by Consultant Gynaecologists or Oncologists.
Monitoring of therapy in ovarian carcinoma and pre-operative
assessment of suspected ovarian malignancy (risk malignancy
Pre-operative assessment and follow-up of bladder carcinoma.
NOTE: If a patient is having serial tumour marker levels
monitored the tests must all be done at the same laboratory as
there are significant variations between assays
Run daily Monday to Friday
Causes for Rejection
Not meeting specific criteria for analysis.
Less than 35 U/mL
Half-life in Serum
Approx. 5 days
Moderately raised CA125 (usually <100 kU/L) may be due to
normal physiology (e.g. pregnancy or menstruation) or a benign
process (e.g. endometriosis, benign ovarian cysts).
High concentrations of CA125 are more likely to be associated
with malignancy; 98% of post-menopausal and 49% of pre-menopausal
women with CA125 >700 kU/L have malignant disease
High CA125 levels may be seen in patient with non-ovarian
intra-abdominal malignancies, e.g. lymphoma
CA125 levels are >300 kU/L in 50% patients with stage I
ovarian carcinoma and in over 90% of patients with stage II, III,
or IV disease
CA-125 is raised in liver disease, 70% of patients with
cirrhosis and 13% of patients with liver fibrosis have a raised