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Test ID: Cancer Antigen-125 (CA-125)
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Cancer Antigen-125 (CA-125)
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Useful For
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To monitor treatment for ovarian cancer therapy or to detect cancer recurrence.
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Method name and description
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Electrochemiluminescence immunoassay (ECLIA) intended for use on the cobas e immunoassay analyzer. Patient sample, a biotinylated monoclonal CA 125 specific antibody, and a monoclonal CA 125 specific antibody labeled with a ruthenium complex form a sandwich complex. After addition of streptavidin-coated microparticles, the complex becomes bound to the solid phase via interaction of biotin and streptavidin. The reaction mixture is aspirated into the measuring cell where the microparticles are magnetically captured onto the surface of the electrode. Unbound substances are then removed with ProCell/ProCell M. Application of a voltage to the electrode then induces chemiluminescent emission which is measured by a photomultiplier.Results are determined via a calibration curve which is instrument specifically generated by 2‑point calibration and a master curve provided via the reagent barcode.
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Clinical information
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CA 125 is found in a high percentage of non-mucinous ovarian tumors of epithelial origin and can be detected in serum. It does not occur on the surface epithelium of normal ovaries (adult and fetal).Elevated values are sometimes found in various benign gynecological diseases such as ovarian cysts, ovarian metaplasia, endometriosis, uterus myomatosus or cervicitis. Slight elevations of this marker may also occur in early pregnancy and in various benign diseases (e.g. acute and chronic pancreatitis, benign gastrointestinal diseases, renal insufficiency, autoimmune diseases and others). Markedly elevated levels have been found in benign liver diseases such as cirrhosis and hepatitis. Extreme elevations can occur in any kind of ascites due to malignant and benign diseases. (Roche Cobas Cancer Antigen 125 package insert ; Roche Diagnostic Corp., Indianapolis, IN)
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Specimen type / Specimen volume / Specimen container
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Specimen type: Serum, Plasma
Minimum volume of sample: 1 mL
Serum: Plain tube (red or yellow top)
Plasma: Li‑heparin tube
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Collection instructions / Special Precautions / Timing of collection
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Collect blood by standard venipuncture techniques as per specimen requirements. When processing samples in primary tubes (sample collection systems), follow the instructions of the tube manufacturer.
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Storage and transport instructions
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Storage: 5 days at 2‑ 8 °C
8 hours at 20‑ 25 °C
24 weeks at ‑ 20 °C (±5)
Transport: 2-25°C
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Specimen Rejection Criteria
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Grossly hemolyzed, icteric and lipemic samples, wrong collection container, insufficient sample and heat‑inactivated samples
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Biological reference intervals and clinical decision values
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0-35 U/mL
(The testing method is an Electrochemiluminescence Immunoassay manufactured by Roche Diagnostics and performed on Cobas e801. Results determined by assays using different Manufactures or Methods may not be comparable.)
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Turnaround time / Days and times test performed / Specimen retention time
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Turn-around time:
Routine: One working day
Specimen Retention: 4 days
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