CA 19-9

CA 19-9

Alternate Test Name

Carbohydrate Antigen 199

Epic Mnemonic
Sunquest Mnemonic

LAB777
CA199

Category

Chemistry

Methodology

The Roche Carbohydrate Antigen 19-9 electrochemiluminescent immunoassay is used. Results obtained with different methods or kits cannot be used interchangeably.

Test Performance Schedule

Sunday - Saturday

Result Availability

Within 24 hours

Container

Gold top (SST), Red top (serum), or Green top (lithium heparin) tube

Volume

Pref. Vol.: 1.0 mL serum or plasma
Min. Vol.: 0.5 mL serum or plasma

Collection Instructions

• Routine venipuncture
• Immediately after collection, gently invert tube 5-10 times
• Clot 30 minutes
• Promptly centrifuge 10 minutes
• If no gel barrier is present immediately transfer serum or plasma to a plastic tube and refrigerate
• Properly centrifuged gel barrier tube does not require transfer of serum or plasma to separate tube

Transportation Instructions

Refrigerated

Stability

• Refrigerated: 5 days

Remarks

Medicare Medical Necessity Policy

Biotin, also referred to as Vitamin B7 or Vitamin H, can interfere with this test when taken in mega doses of 5mg (5000 mcg) or more. It is often promoted as a skin and hair beauty aid. Please ask your patients to refrain from taking Biotin or supplements containing Biotin for at least 24 hours before collecting specimens for lab testing.

https://biotinfacts.roche.com/

https://www.fda.gov/medicaldevices/safety/alertsandnotices/ucm586505.htm

CPT Codes

86301

Effective/Revised

7/31/2019

CA 19-9 is a tumor-associated antigen that is reactive with an antibody that was produced in response to immunization with a human colon cancer cell-line. Although the antibody was derived from a colon cancer cell-line, studies have found assays for CA 19-9 more useful in the diagnosis and management of patients with pancreatic cancer than colon neoplasia. CA 19-9 has also been shown to be a more sensitive and specific marker of pancreatic cancer than other serologic markers.

Very little of the CA 19-9 antigen is found in the blood of normal patients or those with benign disorders, but most patients with pancreatic cancer have elevated levels of CA 19-9. Many published studies have shown that patients on various therapeutic regimens with clinically stable or responsive disease had stable or decreasing serum CA 19-9 levels, whereas patients with progressive disease had rising serum levels of CA 19-9.

The clinical management of pancreatic cancer is extremely difficult with most pancreatic cancers having metastasized by the time of diagnosis. Treatment consists of surgical intervention, radiation therapy, chemotherapy and palliative care measures as well as nutritional management. Monitoring the progression of disease is critical in the management of this disease. Therefore, the serial monitoring of CA 19-9 levels as an adjunct to imaging and clinical assessment is valuable in the management of pancreatic cancer patients.