Key takeaways
- CA125 is a blood marker used alongside symptoms and an ultrasound scan, not as a stand-alone screening test for the general population.
- Many things other than cancer can raise CA125, including your period, endometriosis, fibroids, pregnancy and general inflammation.
- NICE guidance uses 35 U/mL as the level that prompts a pelvic ultrasound when a woman has symptoms that could suggest ovarian cancer.
- A normal CA125 result does not rule out ovarian cancer, and a raised result does not diagnose it.
- Symptoms lasting several weeks, including persistent bloating, feeling full quickly, pelvic pain or needing to pass urine more often, should be seen by a doctor.
- The CA125 blood test at Blood London costs £249 plus the £50 blood draw, and includes HE4 and a ROMA score, with results back in 1 working day.
CA125 is a protein measured in the blood that can be raised by ovarian cancer, but also by many common and benign conditions, so it is used alongside your symptoms and an ultrasound rather than as a screening test on its own. Book the CA125 blood test if a clinician has advised it as part of assessing your symptoms.
Book a CA125 blood test at 117a Harley Street: £249 plus the £50 blood draw, results in 1 working day.
Is CA125 a screening test for ovarian cancer?
No, CA125 is not recommended as a screening test for women without symptoms. It is used in a clinical context, alongside your symptoms and an ultrasound scan, when ovarian cancer is one of the possibilities being considered, rather than being offered to the general population as a routine check.
What can raise CA125 apart from cancer?
Many non-cancer conditions can raise CA125, including menstruation, endometriosis, fibroids, pregnancy and general pelvic or abdominal inflammation. This is why a single raised result is not treated as a diagnosis; a clinician weighs it against your age, menopausal status, symptoms and imaging findings.
| Cause of a raised CA125 | Cancer-related? |
|---|---|
| Menstrual period | No |
| Endometriosis | No |
| Fibroids | No |
| Pregnancy | No |
| General inflammation, including in the pelvis or abdomen | No |
| Ovarian cancer, and some other cancers | Yes; needs further assessment |
What level of CA125 leads to further investigation?
NICE guidance uses 35 U/mL as the level that prompts a pelvic ultrasound in a woman with symptoms that could suggest ovarian cancer. This is a trigger for further assessment, not a diagnosis in itself, and your doctor will consider it alongside your ultrasound findings and overall clinical picture.
What symptoms mean I should see a doctor?
See a doctor if you have persistent bloating, feel full quickly when eating, have pelvic or abdominal pain, or need to pass urine more often or urgently, and these symptoms have lasted several weeks or keep coming back, especially if you are 50 or over. Unexplained weight loss, tiredness or a change in bowel habit are also worth mentioning. These are the symptoms NICE identifies as warranting assessment, and they are common to many conditions, most of which are not cancer, but they are worth having checked. A lump or swelling in your tummy, or any bleeding after the menopause, should be seen by a GP promptly.
What does the CA125 blood test at Blood London include?
The CA125 blood test includes CA-125, HE4 and a calculated ROMA score, giving a more structured picture than CA125 alone. Menopausal status is required to calculate the ROMA score, so let the clinic know this when you book. For a broader hormone picture alongside CA125, the Female Hormone Blood Test adds FSH, LH, oestradiol and testosterone (£245 plus the £50 blood draw, results in 1 working day). You can see the full range of organ-specific marker tests on the cancer marker blood tests page.
Can a normal CA125 rule out ovarian cancer?
No. A normal CA125 result does not exclude ovarian cancer, and some ovarian cancers do not raise CA125 at all, particularly in the early stages. This is why the test is used alongside an ultrasound and your symptoms, rather than being relied on by itself.
How CA125 testing works at our Harley Street clinic
As with all our private blood tests in London, you can book the CA125 blood test online or walk in at 117a Harley Street, seven days a week. The test costs £249 plus the £50 blood draw, and results, including the HE4 and ROMA score, are usually back within 1 working day by email. The clinical team will confirm any preparation and suitability before your appointment. You can add a doctor review of your report to your test for £75. If you would like your result discussed alongside your symptoms and an examination, a specialist gynaecology consultation at Gynae Clinic can take this further.
Book your CA125 blood test online, or walk in seven days a week at 117a Harley Street.
Frequently asked questions
Does CA125 diagnose ovarian cancer?
No. CA125 supports an assessment alongside your symptoms and an ultrasound scan; it does not diagnose or exclude ovarian cancer on its own.
Can CA125 be raised by something other than cancer?
Yes. Your period, endometriosis, fibroids, pregnancy and general inflammation can all raise CA125, which is why the result is read in context rather than alone.
What is the ROMA score?
ROMA combines CA125 and HE4 with your menopausal status into a single calculated score, used alongside imaging to help assess ovarian risk. It is not a diagnosis by itself.
Should every woman have a CA125 test?
No. CA125 is not recommended as a general screening test for women without symptoms; it is used when a clinician is assessing specific symptoms.
How quickly will I get my CA125 result?
Results, including HE4 and the ROMA score, are usually available within 1 working day by email.
References
- NICE guideline NG12: Suspected cancer, recognition and referral
- NHS: Ovarian cancer
- Cancer Research UK: CA125 test
- Lab Tests Online UK: CA125 test