Educational information only. CA-125 is a test that should be requested and interpreted by a qualified clinician. It is not a stand-alone test for cancer and is not recommended for general screening. Testing is performed in NATA-accredited laboratories to ISO 15189 standards.

What is CA-125?

CA-125 is a protein that can be measured in the blood and is associated with the ovaries, among other tissues. It is best known in the context of ovarian conditions, but it is a marker to be interpreted with considerable care rather than read at face value.

Why it is used carefully

CA-125 is not specific. It can be raised by many common and benign conditions, including menstruation, endometriosis, fibroids, pregnancy and other inflammation in the abdomen. Because of this lack of specificity, it is not recommended as a screening test for the general population and is instead used by clinicians in particular situations, such as monitoring a known condition.

What your results can mean

Raised

A raised CA-125 has many possible explanations, most of them benign, and by itself it does not diagnose anything. It is interpreted only within a specific clinical context by your doctor.

Within the expected range

A CA-125 in the expected range is one piece of information among many and does not rule conditions in or out on its own.

Reference ranges in Australia

CA-125 is reported in units per millilitre (U/mL), with a laboratory-specific reference value. Because the marker is so easily influenced by benign factors, interpretation belongs entirely with your clinician.

A note on CA-125 testing

CA-125 is not a general screening test and can cause unnecessary worry if used without clear clinical reason. At Precursor, tumour markers are used only under clinician direction in appropriate circumstances. If you have concerns, the best step is a conversation with your GP or a Precursor clinician about whether this testing is appropriate for you.