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Test Code 199PT Carbohydrate Antigen 19-9 (CA 19-9), Peritoneal Fluid

Reporting Name

CA 19-9, Peritoneal Fluid

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Useful For

An adjunct to cytology to differentiate between malignancy-related ascites and benign causes of ascites formation

Method Name

Immunoenzymatic Assay


Specimen Required


Patient Preparation: For 12 hours before specimen collection do not take multivitamins or dietary supplements containing biotin (vitamin B7), which is commonly found in hair, skin, and nail supplements and multivitamins.

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

Specimen Volume: 2 mL


Specimen Type

Peritoneal

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
Gross icterus OK

Reference Values

An interpretive report will be provided.

Interpretation

A peritoneal fluid carbohydrate antigen 19-9 (CA 19-9) concentration greater than 32 U/mL is suspicious, but not diagnostic, of a malignancy-related ascites. This clinical decision limit cutoff yielded 44% sensitivity and 93% specificity in a study of 137 patients presenting with ascites. However, ascites caused by malignancies not associated with increase serum CA 19-9 concentrations, including lymphoma, mesothelioma, leukemia, and melanoma, routinely had CA 19-9 concentrations less than 32 U/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 CA 19-9 levels in serum.

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
199PT CA 19-9, Peritoneal Fluid 50781-4

 

Result ID Test Result Name Result LOINC Value
199PN CA 19-9, Peritoneal Fluid 50781-4
SITEE Site 39111-0