Carbohydrate Antigen (CA) 19-9 (Serial Monitor)
Use
The Carbohydrate Antigen (CA) 19-9 test is used for long-term serial monitoring of patients undergoing cancer treatment, particularly for pancreatic cancer. CA 19-9 is a tumor marker that can help in assessing the response to treatment or in surveillance after surgical resection. It is important to monitor CA 19-9 levels to track changes over time, as values obtained with different assay methods cannot be used interchangeably.
Special Instructions
The patient's Social Security number must be submitted to monitor serial results. Only one assay method should be consistently used to monitor a patient's therapy to avoid variations between different testing methods. Patients must refrain from consuming biotin supplements at least 72 hours prior to specimen collection, as high doses can interfere with test results.
Limitations
The CA 19-9 assay results cannot be interpreted as absolute evidence of the presence or absence of malignant disease. Interference may occur if the sample comes from a person consuming high doses of biotin, which could lead to inaccurate results. Variations from different test methods may cause discrepancies; thus, it is suggested to use one method consistently for serial testing.
Methodology
Immunoassay (ECLIA)
Biomarkers
LOINC Codes
- 24108-3
- 80563-0
Result Turnaround Time
1 day
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
1 mL
Minimum Volume
0.7 mL
Container
Gel-barrier tube (preferred) or red-top tube
Collection Instructions
If a red-top tube is used, transfer separated serum to a plastic transport tube.
Patient Preparation
Patients should avoid biotin consumption at least 72 hours prior to specimen collection.
Storage Instructions
Room temperature