Carbohydrate Antigen 19-9 (CA 19-9), Pleural Fluid
Use
This test is used as an adjuvant to cytology and imaging studies to differentiate between nonmalignant and malignant causes of pleural effusions. Elevated pleural fluid concentrations of CA 19-9 are associated with malignancies like cholangiocarcinoma, colorectal, stomach, bile duct, lung, ovarian, and pancreatic cancers. The presence of CA 19-9 in pleural fluid, therefore, can potentially enhance cytological findings and guide clinical decision-making.
Special Instructions
For 12 hours before specimen collection, the patient should not take multivitamins or dietary supplements containing biotin (vitamin B7). The specimen should be collected in a plain, plastic, screw-top tube, with a preferred volume of 2 mL. If not ordering electronically, complete, print, and send an Oncology Test Request (T729) with the specimen.
Limitations
CA 19-9 testing has limited utility as a stand-alone diagnostic test as it is not specific for malignancy. Results should be correlated with cytology, imaging, and other clinical tests. False negatives can occur in certain malignancies, such as mesothelioma and lymphoma. Variability in CA 19-9 secretion and Lewis antigens in individuals could result in misleading low or negative results. Interfering substances like human anti-mouse antibodies and non-malignant conditions such as liver cirrhosis, pancreatitis, gallstones, and cholecystitis may cause elevated CA 19-9 levels, complicating test interpretation.
New York Approved
Methodology
Immunoassay (Other)
Biomarkers
LOINC Codes
- 19163-5
- 19163-5
- 39111-0
Result Turnaround Time
1-3 days
Related Documents
For more information, please review the documents below
Specimen
Other
Volume
2 mL
Minimum Volume
0.5 mL
Container
Plain, plastic, screw-top tube
Collection Instructions
Patient should not take multivitamins or dietary supplements containing biotin (vitamin B7) for 12 hours before specimen collection. Collect pleural fluid via thoracentesis.
Patient Preparation
For 12 hours before specimen collection, the patient should not take multivitamins or dietary supplements containing biotin (vitamin B7).
Storage Instructions
Pleural Fluid should be stored frozen (preferred) for up to 90 days, ambient for up to 7 days, and refrigerated for up to 14 days.
Causes for Rejection
Gross hemolysis
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 7 days |
| Refrigerated | 14 days |
| Frozen | 90 days |