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HelpTest Code CEAPT Carcinoembryonic Antigen (CEA), Peritoneal Fluid
Reporting Name
CEA, Peritoneal FluidUseful For
An adjunct to cytology to differentiate between malignancy-related and benign causes of ascites formation
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
PeritonealSpecimen Required
Container/Tube: Plain, plastic, screw top tube
Specimen Volume: 2 mL
Specimen Minimum Volume
0.5 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Peritoneal | Frozen (preferred) | 90 days | |
| Ambient | 7 days | ||
| Refrigerated | 7 days |
Reference Values
An interpretive report will be provided.
Day(s) Performed
Monday through Saturday
Test Classification
This test has been modified from the manufacturer's instructions. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
82378
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| CEAPT | CEA, Peritoneal Fluid | 40622-3 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| CEAPN | CEA, Peritoneal Fluid | 40622-3 |
| SITED | Site | 39111-0 |
Clinical Information
Malignancy accounts for approximately 7% of cases of ascites formation. Malignant disease can cause ascites by various mechanisms including peritoneal carcinomatosis (53%), massive liver metastasis causing portal hypertension (13%), peritoneal carcinomatosis plus massive liver metastasis (13%), hepatocellular carcinoma plus cirrhosis (7%), and chylous ascites due to lymphoma (7%). The evaluation and diagnosis of malignancy-related ascites is based on the patient clinical history, ascites fluid analysis, and imaging tests.
The overall sensitivity of cytology for the detection of malignancy-related ascites ranges from 58% to 75%. Cytology examination is most successful in patients with ascites related to peritoneal carcinomatosis as viable malignant cells are exfoliated into the ascitic fluid. However, only approximately 53% of patients with malignancy-related ascites have peritoneal carcinomatosis. Patients with other causes of malignancy-related ascites almost always have a negative cytology.
Carcinoembryonic antigen (CEA) is a glycoprotein that is shed from the surface of malignant cells. Measurement of CEA in ascitic fluid has been proposed as a helpful test in detecting malignancy-related ascites given the limited sensitivity of cytology.
Interpretation
A peritoneal fluid carcinoembryonic antigen (CEA) concentration greater than 6.0 ng/mL is suspicious, but not diagnostic, of malignancy-related ascites. This clinical decision limit cutoff yielded 48% sensitivity and 99% specificity in a study of 137 patients presenting with ascites. CEA concentrations were significantly higher in ascites caused by malignancies known to be associated with elevated serum CEA levels, including lung, breast, ovarian, gastrointestinal, and colorectal cancers. However, ascites caused by other malignancies, such as lymphoma, mesothelioma, leukemia, and melanoma and hepatocellular carcinoma, routinely had CEA concentrations less than 6.0 ng/mL. Therefore, negative results should be interpreted with caution, especially in patients who have, or are suspected of having, a malignancy not associated with elevated CEA levels in serum.
Method Description
The instrument used is Beckman Coulter UniCel DXI 800. The Access CEA assay is a 2-site immunoenzymatic sandwich assay using mouse monoclonal carcinoembryonic antigen (CEA) antibodies that react with different epitopes of CEA. A sample is added to a reaction vessel, along with the first CEA monoclonal antibodies-alkaline phosphatase conjugate and the second CEA monoclonal antibodies bound to paramagnetic particles. The incubation is followed by a magnetic separation and washing. A chemiluminescent substrate is added to the vessel, and the light generated by the reaction is measured with a luminometer. The light production is proportional to the concentration of CEA in the sample. The amount of analyte in the sample is determined by means of a stored, multipoint calibrator curve.(Package insert: Access CEA Assay, Beckman Coulter, Inc; 2020)
Reject Due To
| Gross hemolysis | Reject |
Method Name
Immunoenzymatic Assay
Forms
If not ordering electronically, complete, print, and send an Oncology Test Request (T729) with the specimen.