Cancer Antigen 125

Cancer Antigen 125, also called CA-125, is a tumor marker. It is reported as a laboratory measurement, with reference information used to describe how the result should be read and understood.

Cancer Antigen 125 is measured from a serum sample collected through a blood test. Because fasting is not required, the test can be arranged without avoiding food beforehand. When scheduling the collection, it is still useful to confirm any preparation instructions provided by the testing laboratory.

The result is reported in U/mL and should be read alongside the reference and optimal ranges shown with the test. For this marker, lower values are considered preferable. The displayed male and female ranges provide the relevant comparison points for interpretation. A clinician can help place the result in context alongside the reason for testing and any other relevant findings.

Cancer Antigen 125 is measured in serum and reported in U/mL. Results are interpreted against the reference range printed on the laboratory report. A result within that range is within the laboratory’s usual comparison interval, while the optimal range is a narrower target used for a tighter interpretation. Because lower values are considered better for this biomarker, position within these ranges matters, but it should not be viewed in isolation.

Laboratories may use different ranges or units, so a number is meaningful only alongside the range and units shown on the same report. A single value is not a diagnosis and does not, by itself, establish the presence or absence of a medical condition. Results outside the reported reference range should be discussed with a clinician, who can interpret them in context.