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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
Method Name
Immunoenzymatic Assay
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 |
Reject Due To
| Gross hemolysis | Reject |
Reference Values
An interpretive report will be provided.
Day(s) Performed
Monday through Saturday
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.
Cautions
Do not use peritoneal fluid carcinoembryonic antigen (CEA) concentration as absolute evidence of the presence or the absence of malignant disease. The CEA result should be interpreted in conjunction with information from the clinical evaluation of the patient and other diagnostic procedures.
In some immunoassays, the presence of unusually high concentrations of analyte may result in a high-dose "hook" effect. This may result in a lower or even normal measured analyte concentration. If the reported result is inconsistent with the clinical presentation, the laboratory should be alerted for troubleshooting.
In rare cases, some individuals can develop antibodies to mouse or other animal antibodies (often referred to as human anti-mouse antibodies [HAMA] or heterophile antibodies), which may cause interference in some immunoassays. Caution should be used in interpretation of results and the laboratory should be alerted if the result does not correlate with the clinical presentation.
CEA values are method-dependent; therefore, the same method should be used if patients are serially monitored.
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)