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Test Code PF199 Carbohydrate Antigen 19-9 (CA 19-9), Pleural Fluid

Reporting Name

CA 19-9, Pleural Fluid

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Useful For

An adjuvant to cytology and imaging studies to differentiate between nonmalignant and malignant causes of pleural effusions

Method Name

Immunoenzymatic Assay


Specimen Required


Patient Preparation: For 12 hours before specimen collection, patient should not take multivitamins or dietary supplements (eg, hair, skin, and nail supplements) containing biotin (vitamin B7).

Source: Pleural fluid, thoracentesis fluid

Container/Tube: Plain, plastic, screw-top tube

Specimen Volume: 2 mL


Specimen Type

Pleural Fluid

Specimen Minimum Volume

0.5 mL (Samples <0.5 mL may be rejected)

Specimen Stability Information

Specimen Type Temperature Time
Pleural Fluid Frozen (preferred) 90 days
  Refrigerated  14 days
  Ambient  7 days

Reject Due To

Gross hemolysis Reject
Gross icterus OK

Reference Values

An interpretive report will be provided.

Interpretation

A pleural fluid carbohydrate antigen 19-9 (CA 19-9) concentration of 20.0 U/mL or higher is suspicious, but not diagnostic, of a malignant source of the effusion. This cutoff yielded a sensitivity of 35%, specificity of 95%, and positive predictive value of 88% in a study of 200 patients presenting with effusion. CA 19-9 concentrations were significantly higher in effusions caused by CA 19-9-secreting malignancies, including cholangiocarcinoma, colorectal, stomach, bile duct, lung, ovarian, and pancreatic cancers. However, effusions caused by non-CA 19-9-secreting malignancies, including lymphoma, mesothelioma, leukemia, and melanoma, routinely had CA 19-9 concentrations below 20.0 U/mL. Therefore, negative results should be interpreted with caution, especially in patients who have or are suspected of having a non-CA 19-9-secreting malignancy.

 

Correlation of all tumor marker results with cytology and imaging is highly recommended.

Day(s) Performed

Monday through Saturday

Report Available

1 to 3 days

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

86301

LOINC Code Information

Test ID Test Order Name Order LOINC Value
PF199 CA 19-9, Pleural Fluid 19163-5

 

Result ID Test Result Name Result LOINC Value
P199 CA 19-9, Pleural Fluid 19163-5
SITE8 Site 39111-0

Forms

If not ordering electronically, complete, print, and send an Oncology Test Request (T729) with the specimen.