Sorted By Test Name - Mayo Medical Laboratories

199PC
89508
199PT
61530
Clinical References: The 2009 CLSI Standards for Antimicrobial Susceptibility Testing. CLSI
Audioconference. Janet Hindler. Original air date: January 21, 2009
Carbohydrate Antigen 19-9 (CA 19-9), Pancreatic Cyst Fluid
Clinical Information: Carbohydrate antigen 19-9 (CA 19-9) is a modified Lewis(a) blood group
antigen, and has been used as a tumor marker. Serum CA 19-9 concentrations may be elevated in patients
with gastrointestinal malignancies such as cholangiocarcinoma, colon cancer, or pancreatic cancer. While
serum CA 19-9 is neither sensitive nor specific for pancreatic cancer, concentrations of CA 19-9 in
pancreatic cyst fluid may help determine whether a pancreatic cyst is benign. Cystic lesions of the
pancreas are of various types: -Benign cysts: - Inflammatory cysts (pseudocysts) - Serous cysts (serous
cystadenoma) -Mucinous cysts: - Premalignant (mucinous cystadenoma) - Malignant
(cystadenocarcinoma, intrapapillary mucinous neoplasia) Pancreatic cyst fluid CA 19-9 results should be
used in conjunction with imaging studies, cytology, and other cyst-fluid tumor markers, such as
carcinoembryonic antigen (CEA) and amylase.
Useful For: As an adjunct in the assessment of pancreatic cysts, when used in conjunction with
carcinoembryonic antigen (CEA), amylase, imaging studies and cytology.
Interpretation: Cyst fluid carbohydrate antigen 19-9 (CA19-9) concentrations < or =37 U/mL indicate
a low risk for a mucinous cyst, and are more consistent with serous cystadenoma or pseudocyst. The
sensitivity and specificity are approximately 19% and 98%, respectively, at this concentration. Correlation
of these test results with cytology and imaging is recommended.
Reference Values:
An interpretive report will be provided.
Clinical References: 1. Snozek CL, Jenkins SM, Bryant SC, et al: Analysis of CEA, CA19-9 and
amylase in pancreatic cyst fluid for diagnosis of pancreatic lesions. Clin Chem 2008;54(6 Suppl
S):A126-127 2. van der Waaij LA, van Dullemen HM, Porte RJ: Cyst fluid analysis in the differential
diagnosis of pancreatic cystic lesions: a polled analysis. Gastrointest Endosc 2005;62:383-389 3. Khalid
A, Brugge W: ACG practice guidelines for the diagnosis and management of neoplastic pancreatic cysts.
Am J Gastroenterol. 2007 Oct;102(10):2339-2349
Carbohydrate Antigen 19-9 (CA 19-9), Peritoneal Fluid
Clinical Information: Malignancy accounts for approximately 7% of cases of ascites formation.
Malignant disease can cause ascites by various mechanisms including: peritoneal carcinomatosis (53%),
massive liver metastasis causing portal hypertension (13%), peritoneal carcinomatosis plus massive liver
metastasis (13%), hepatocellular carcinoma plus cirrhosis (7%), and chylous ascites due to lymphoma
(7%). The evaluation and diagnosis of malignancy-related ascites is based on the patient clinical history,
ascites fluid analysis, and imaging tests. The overall sensitivity of cytology for the detection of
malignancy-related ascites ranges from 58% to 75%. Cytology examination is most successful in patients
with ascites related to peritoneal carcinomatosis as viable malignant cells are exfoliated into the ascitic
fluid. However, only approximately 53% of patients with malignancy-related ascites have peritoneal
carcinomatosis. Patients with other causes of malignancy-related ascites almost always have a negative
cytology. Carbohydrate antigen 19-9 (CA 19-9) is a modified Lewis(a) blood group antigen. CA 19-9 may
be elevated in the serum patients with gastrointestinal malignancies such as cholangiocarcinoma,
pancreatic cancer, or colon cancer. Measurement of CA 19-9 in ascitic fluid is sometimes used in
combination with cytology for detecting malignancy-related ascites.
Useful For: An adjunct to cytology to differentiate between malignancy-related ascites and benign
causes of ascites formation
Interpretation: A peritoneal fluid carbohydrate antigen 19-9 (CA 19-9) concentration >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
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