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

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Reporting Name

CA 19-9, Peritoneal Fluid

Specimen Type

Peritoneal


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


Reject Due To

Gross hemolysis Reject
Gross icterus OK

Specimen Stability Information

Specimen Type Temperature Time Special Container
Peritoneal Frozen (preferred) 90 days
  Ambient  7 days
  Refrigerated  7 days

Specimen Minimum Volume

0.5 mL

Day(s) Performed

Monday through Saturday

Specimen Retention Time

14 days

Report Available

1 to 3 days

Reference Values

An interpretive report will be provided.

Useful For

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

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

Supportive Data

An in-house study was performed to select a clinical decision limit to differentiate between malignancy-related benign causes of ascites with high specificity. The study included 83 cases of benign ascites and 54 cases of malignancy-related ascites. Within the malignancy-related ascites, there were 9 specimens with malignancies known not to secrete carbohydrate antigen 19-9 (CA 19-9) in serum (lymphoma, leukemia, melanoma, sarcoma, and neuroendocrine tumors). Amongst the group that are known to secrete CA 19-9 in serum (n=45), there were the following malignancies: pancreatic, breast, gastric, colon, bladder, cholangiocarcinoma, gynecological cancers, peritoneal carcinomatosis, and hepatocellular carcinoma. Using a clinical decision limit cutoff of greater than 32 U/mL, the specificity was 93% for the benign ascites group. The sensitivity was 49% for those malignancies associated with elevated CA 19-9 in serum.