Carbohydrate antigen CA 19-9 in serum

Reference values ​​CA 19-9 in blood serum - up to 37 IU / ml. Half-life is 5 days.

CA 19-9 is a glycoprotein found in the fetal epithelium of the pancreas, stomach, liver, small and large intestine, lungs. In adults this Ag is a marker of the glandular epithelium of most internal organs and a product of their secretion. It should be noted that the antigenic determinant Ag CA 19-9 and Ar of the Lewis blood group( Le( ab-)) are encoded by a single gene, which is absent in 7-10% of the population in the population. So such a number of people genetically lacks the ability to synthesize CA 19-9, therefore, even in the presence of a malignant tumor from the glandular epithelium, the level of the marker in the serum is not determined or its concentration is at very low values. CA 19-9 is excreted exclusively with bile, so even insignificant cholestasis can cause a significant increase(up to 100 IU / ml and even up to 500 IU / ml) can also be observed in benign and inflammatory diseases of the digestive tract( in 50% of cases of pancreatitis) and in the liver( hepatitis, cirrhosis), in the blood.in cystic fibrosis and inflammatory diseases of the pelvic organs in women( in 25% of cases of endometriosis and uterine myoma). In these groups of patients, CA 19-9 can be used as a marker for monitoring the treatment of these diseases.

As a marker of pancreatic carcinoma CA 19-9 has a sensitivity of 82%.No correlation was found between the concentration of the marker and the mass of the tumor. However, its level above 10 000 IU / ml indicates the presence of distant metastases. The study of the level of CA-19-9 in dynamics provides valuable information for evaluating the effectiveness of

surgical treatment and determining the prognosis. With a low level of CA-19-9 in the blood( 64-690 IU / ml), life expectancy averages 17 months, at a level of 75-24 000 IU / ml - 4 months [Staab H. J., 1986].

Ca 19-9 has a sensitivity of 50-75% for hepatobiliary carcinoma. Currently, CA 19-9 is the second most important marker( after CEA) for the diagnosis of gastric carcinoma. Its increase is observed in 42-62% of patients with stomach cancer. The sensitivity of CA 19-9 is:

■ in patients with pancreatic cancer - 82% at a separation point of more than 80 IU / mL;

■ in patients with liver cancer - 76% at a separation point of more than 80 IU / ml;

■ in patients with gastric cancer - 29% at a separation point of more than 100 IU / ml;

■ in patients with colorectal cancer - 25% at a separation point of more than 80 IU / ml.

Determination of CA 19-9 serum content is used:

■ for diagnosis and monitoring of pancreatic cancer treatment;

■ for early detection of pancreatic tumor metastasis;

■ for monitoring of colon, stomach, gallbladder and bile duct cancer;

■ for diagnosis and monitoring of ovarian cancer treatment( in combination with CA-125 and CA 72-4).