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Cancer Antigen 19-9
|Performed by||China Basin Chemistry|
|In House Availability||Tuesday, Friday (day shift)|
|Method||Chemiluminescent Immunoassay (Siemens Centaur)|
|Container type||Gold top|
|Amount to Collect||2 mL blood|
|Preferred volume||1 mL serum|
|Min. Volume||0.5 mL serum|
|Processing notes||Freeze serum at -20°C.|
|Normal range||< 36 U/mL|
|Stability||Refrigerated 5 days, frozen at -20C 3 months|
|Turn around times||1-8 days|
|Additional information||CA 19-9 is a tumor-associated carbohydrate antigen that has been found to be elevated in the serum of some patients with cancers of the pancreas, stomach, colon, bile duct, ovaries, endometrium, or lung. The serum levels of this antigen can also be elevated in benign conditions such as pancreatitis, cholangitis, and endometriosis. Although the levels of CA19-9 tend to be higher in malignant versus benign conditions, there is a substantial overlap zone, and interlaboratory variability in the measurement of CA 19-9 appears to be substantial (CV ~30% in a recent CAP survey). In one recent study of patients with pancreatic cancer versus benign pancreatic disease, the sensitivity of an elevated CA 19-9 measurement was 76%, with a specificity of 87%.
Since the CA 19-9 antigen is closely related to the Lewis blood group antigens, patients who lack Lewis antigen (approximately 7% of the general public) cannot produce CA 19-9. Additionally, the secretor status of the patient will have an influence on CA 19-9 levels.
Internal Medicine 38: 840-841 (1999).
Am. J. Gastroenterology 94:1941-1946 (1999).
Clin Chem 45:54-61 (1999).
|Medical Necessity?||Yes. Click here for more information|
|Last Updated||9/15/2011 3:30:42 PM|
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