Ca-125 is a marker for ovarian cancer. The blood test alone is not diagnostic of ovarian cancer and some patients with raised levels do not have the condition. However a raised level prompts investigations such as scans which can help to determine if the condition is present

Early detection of cancers can lead to much better outcomes. Blood tests can pick up some early cancer markers. This can prompt further investigation especially if accompanied by symptoms. Blood cancer markers are not an exact science but can also be used to track the success of some cancer treatments.