Cancer Antigen 125, (Ca 125)
Label Mnemonic: CA125
Epic Lab Code: LAB155
Downtime Form: A-1a Doctor/Provider Orders - Pathology Core and Specialty Care Nursery
6240 RCP
Collection Medium:
Plasma Separator Tube 4.5 mL
Alternate Collection Media:
Call laboratory for additional acceptable specimen collection containers.
3 mL whole blood in plasma separator tube or TWO Microtainer® devices
Testing Schedule:
24 hrs/day, 7 days a week, including holidays.
Turn Around Time:
1 hour (upon receipt in laboratory)
Reference Range:
0-34 U/mL
This assay may be significantly impacted by high-dose biotin (>5 mg dose) taken within previous 12 hours. High concentrations of biotin may lead to falsely decreased results. These concentrations may be found in patients taking over-the-counter supplements with biotin content much higher than nutritional requirements for biotin. Specimens should not be collected until at least 12 hours after the last dose.
Test Limitations:
As with all tests containing monoclonal antibodies, erroneous findings may be obtained from samples taken from patients who have been treated with monoclonal mouse antibodies (e.g., OC 125) or who have received them for diagnostic purposes. In rare cases, interference due to extremely high titers of antibodies to ruthenium can occur. Elecsys CA125 II contains additives which minimize these effects. Extremely high titers of antibodies to streptavidin can occur in isolated cases and cause interference. For diagnostic purposes, the Elecsys CA125 II finding should always be assessed in conjunction with the patient's medical history, clinical examination and other findings.

Hemolysis: No significant interference up to an H index of 3200 (approximate hemoglobin concentration: 3200 mg/dL).

Lipemia: No significant interference up to an L index of 2000 (approximate triglycerides concentration: 4000 mg/dL). Note there is poor correlation between turbidity and triglyceride concentration.

Icterus: No significant interference up to an I index of 66 (approximate conjugated and unconjugated bilirubin concentration: 66 mg/dL).
Electrochemiluminescence Immunoassay
CPT Code:
See also:
Cancer Antigen 125, Other, Body Fluid
See Additional Information:
Biotin Interference with Immunoassays