Carcinoembryonic Antigen (CEA), Peritoneal Fluid
Use
The Carcinoembryonic Antigen (CEA) assay in peritoneal fluid is used as an adjunct to cytology for differentiating between malignancy-related and benign causes of ascites formation. Malignancy accounts for approximately 7% of cases of ascites, and measuring CEA in ascitic fluid helps detect malignancy-related ascites, complementing the limited sensitivity of cytology, which ranges from 58% to 75%. This test is particularly useful for patients with malignancy-related ascites where viable malignant cells are exfoliated into the ascitic fluid, such as peritoneal carcinomatosis.
Special Instructions
If not ordering electronically, complete, print, and send an Oncology Test Request (T729) with the specimen. The test must use plain, plastic, screw-top tubes for sample collection, and peritoneal washings should not be used.
Limitations
This test should not be used as absolute evidence of the presence or absence of malignant disease. High concentrations may result in a 'hook' effect, leading to inaccurate readings. Interferences can result from human anti-mouse antibodies (HAMA) or heterophile antibodies. Such interferences should be communicated to the laboratory if results don't match the clinical presentation. Different methodologies may yield different quantitative results, so consistency in testing methods is crucial when serial measurements are required.
New York Approved
Methodology
Immunoassay (ELISA)
Biomarkers
LOINC Codes
- 40622-3
- 40622-3
- 39111-0
Result Turnaround Time
1-3 days
Related Documents
For more information, please review the documents below
Specimen
Body Fluid
Volume
2 mL
Minimum Volume
0.5 mL
Container
Plain, plastic, screw top tube
Collection Instructions
Source options include peritoneal, abdominal, ascites, and paracentesis fluid, but peritoneal washings are not acceptable.
Causes for Rejection
Gross hemolysis
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 7 days |
| Refrigerated | 7 days |
| Frozen | 90 days |