CA 125
|
Assay |
CA 125 |
|
Key Words |
CA125 |
|
Specimen Collection |
Serum (brown), Plasma (orange) |
|
Turnaround Time |
72hrs |
|
Test Indications |
Cancer antigen 125 (CA125) is used as a tumour marker for ovarian cancer, in diagnosis (only for differential diagnosis of pelvic masses, particularly in post-menopausal women), prognosis, detecting recurrence and monitoring treatment. When used for diagnosis, patients with a CA125 >35IU/mL should have an ultrasound of the abdomen and pelvis, and a Risk of Malignancy Index can then be calculated. For more information see NICE guideline 122. CA125 is not usually tested in male patients but is used in the follow-up of patients with pseudomyxoma peritoei (PMP, an uncommon disease characterised by mucinous ascites usually originating from a perforated mucinous tumour of the appendix) alongside CEA and CA19-9. Requesting of CA125 in male patients is restricted to the follow-up of PMP. |
|
Limitations/Interferences |
No known common methodological interferences. Because of common embryological origins, CA125 is raised in conditions affecting the endometrium and pleura. Irritation/inflammation of these tissues (ascites/pneumonia) causes increased CA125 levels as do cancers of the breast, cervix, endometrium, liver, lung, pancreas, peritoneum and uterus, and non-Hodgkin’s lymphoma. Other benign conditions that may cause elevations include acute hepatitis, pancreatitis, acute urinary retention, arthritis, chronic liver disease, chronic renal failure, colitis, congestive cardiac failure, cystic fibrosis, diabetes, diverticulitis, endometriosis, irritable bowel syndrome, fibroids, menstruation, ovarian hyperstimulation, pericarditis, pregnancy, sarcoid, systemic lupus erthyematosus or recurrent ischaemic strokes in patients with metastatic cancer. Laproscopy may also affect interpretation.
N.B. CA 125 values determined on patient samples by different testing procedures cannot be directly compared with one another. |
|
Reference Range |
Less than 35 U/mL (females only) |
|
Analytical Error [1] |
3.2% |
|
26.7% |
|
|
Minimum retesting interval |
Requests made within 14 days of a previous result of a patient are intervened |
