CA 15-3

DESCRIPTION: CA 15-3 – Sample Serum, plasma, cerebrospinal fluid, pleura, ascites Blood is taken in a vacuum tube (vacutube) with a red cap without additives or in a vacuum tube containing gel or in a vacuum tube (vacutube) with a green cap (Li-heparinate) or a purple cap (EDTA). The stability of the sample (serum, plasma) at -20°C is 3 months, at 4 – 8°C is 7 days. Carcinoma antigen (CA 15-3) is a tumor antigen that is specific for breast cancer. CA 15-3 is named after the antigen identified by the monoclonal antibody 115D8 and DF3 (“15” – stands for 115D8 “capture antibody” and “3” refers to the DF3 labeled antibody). However, like other tumor markers, Ca 15-3 can be elevated in a large number of pathological conditions in the abdomen and in lung cancer patients. Normal values of CA 15-3 are up to 30 U/ml. Elevated values of CA 15-3 have no significance in detecting new cases of breast cancer. In general, CA 15-3 is useful as a tumor marker in the follow-up of patients treated for breast cancer, given that its elevation after treatment in a large percentage indicates the occurrence of disease recurrence long before it becomes clinically evident. An increase in the value of CA 15-3 correlates with the progression of the disease, and a decrease with a partial or complete response to therapy. The CA 15-3 test is not suitable and is not recommended for screening or diagnosis. DETERMINATION: Recommended method of the Croatian Chamber of Medical Biochemists: Analyte/search: Carcinoma antigen (CA 15-3) Sample: Serum Measurement units: kIU/L The method of choice for determination is the immunometric method. RIA ELISA ECLIA CLINICAL SIGNIFICANCE: CA 15-3 is not a sufficiently sensitive and specific test for the detection of breast cancer. Any increase in CA 15-3 can also originate from other causes. A negative value or a value in the reference range for CA 15-3 does not confirm the absence of cancer. Cancer can be present and CA 15-3 values increase only when the cancer is already advanced. It is recommended that the test be used after breast cancer has already been diagnosed. The level of CA 15-3 should not be determined immediately after the start of therapy, but rather wait a few weeks and only then start monitoring the level of the tumor marker. Ca 15-3 is increased in about 30% of women with localized breast cancer. About 75% of them are invasive breast cancers (cancer that metastasizes or spreads to other organs). Carcinoma antigen CA 15-3 can also be elevated in healthy people, but also in people with other cancers, such as colorectal cancer and benign breast diseases. Determination of the Ca 15-3 test can be requested along with other tests such as estrogen and progesterone receptors, Her2/neu and BRCA-1 and BRCA-2. If an increase in the level of CA 15-3 is found, then it is recommended to determine the concentration of CA 15-3 at certain time intervals in order to monitor the course of the disease. and/or detection of disease recurrence. In the early stage of the disease, usually increased values cannot be found. In principle, high values of CA 15-3 are already obtained in advanced breast cancer. An increase in the level of CA 15-3 correlates with an increase in the cancer mass. The highest values of CA 15-3 are found when metastases have already occurred in the bone and/or in the liver. Moderate or significant increases in CA 15-3 are also found in a variety of diseases including liver and pancreatic carcinoma, cirrhosis, and benign breast disorders. A certain number of healthy people can also have elevated CA 15-3 values, but it is characteristic of such people that the values are elevated but stable – there are no changes. Measuring the level of CA 15-3 is most useful for monitoring the course of treatment in women with breast cancer, especially when it comes to advanced disease. Lung, ovarian and prostate cancers can also cause an increase in this marker, as can non-cancerous conditions such as benign ovarian and breast diseases, endometriosis, pelvic inflammatory disease and hepatitis. Pregnancy and breastfeeding are also associated with elevated values of this marker. A value of CA 15-3 >30 U/ml for many patients means a poor prognosis or/and undetected sites of metastasis. A value of CA 15-3 > 50 U/ml clearly indicates a disease with a metastatic stage. 1) Physiological changes in the concentration of CA 15-3 in the serum (plasma) 2) Pathological changes in the concentration of CA 15-3 in the serum (plasma) A) Increased values of the concentration of CA 15-3 in the serum (plasma) in: Acute hepatitis B / Biliary cirrhosis of the liver unspecified / Renal cell carcinoma / Carcinoma in situ of the breast / Prostate cancer (3) / Colorectal carcinoma / Chronic active hepatitis / Neoplasm, male genitourinary tract / Neoplasm, female genitourinary tract / Malignant neoplasm of the breast / Malignant neoplasm of the pancreas, pancreatic cancer, pancreatic cancer / Malignant neoplasm of the liver, liver cancer, liver cell cancer / Malignant neoplasm of the ovary (Ovarian cancer) / Malignant neoplasm of the lung, lung cancer / Malignant neoplasm of the stomach, gastric cancer, gastric cancer B) Decreased values of CA 15-3 concentration in serum (plasma) at: RISK FACTORS: Elevated values: Liver transplantation Hemodialysis Kidney transplantation Pregnancy RESULT: Reference range (depending on the method): Men and women: less than 25 kIU/L (less than 25 U/ml) Conversion factor: U/ml x 1 = kIU/L Conversion factor (SI – Conv): kIU/L x = U/ml 1 U = 0.8 ng glycoprotein