Test ID: CA25
Cancer Antigen 125 (CA 125), Serum
Secondary ID 
A test code used for billing and in test definitions created prior to November 2011
NY State Approved Indicates the status of NY State approval and if the test is orderable for NY State clients.
Useful For Suggests clinical disorders or settings where the test may be helpful
Evaluating patients' response to cancer therapy, especially for ovarian carcinoma
Predicting recurrent ovarian cancer or intraperitoneal tumor
Method Name A short description of the method used to perform the test
Immunoenzymatic Assay
Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name
Aliases Lists additional common names for a test, as an aid in searching
Cancer Ag 125 (CA 125), S
Cancer Antigen 125
Carbohydrate Antigen 125
OV Monitor
Ovarian Cancer-Related Antibodies
Specimen Type Describes the specimen type needed for testing
Specimen Required Defines the optimal specimen. This field describes the type of specimen required to perform the test and the preferred volume to complete testing. The volume allows automated processing, fastest throughput and, when indicated, repeat or reflex testing.
Container/Tube:
Preferred: Red top
Acceptable: Serum gel
Specimen Volume: 0.6 mL
Specimen Minimum Volume Defines the amount of specimen required to perform an assay once, including instrument and container dead space. Submitting the minimum specimen volume makes it impossible to repeat the test or perform confirmatory or perform reflex testing. In some situations, a minimum specimen volume may result in a QNS (quantity not sufficient) result, requiring a second specimen to be collected.
Reject Due To Identifies specimen types and conditions that may cause the specimen to be rejected
| Hemolysis | Mild OK; Gross reject |
| Lipemia | Mild OK; Gross OK |
| Icterus | NA |
| Other | NA |
Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the laboratory. Alternate acceptable temperature(s) are also included.
| Specimen Type | Temperature | Time |
|---|---|---|
| Serum | Refrigerated (preferred) | 14 days |
| Frozen | 14 days |
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Cancer antigen 125 (CA 125) is a glycoprotein antigen normally expressed in tissues derived from coelomic epithelia (ovary, fallopian tube, peritoneum, pleura, pericardium, colon, kidney, stomach).
Elevated serum CA 125 levels are seen in many patients with cancer of the ovary; the percentage of positive cases increases with cancer stage.
Elevated serum CA 125 levels have been reported in individuals with a variety of nonovarian malignancies including cervical, liver, pancreatic, lung, colon, stomach, biliary tract, uterine, fallopian tube, breast, and endometrial carcinomas.
Elevated serum CA 125 levels have been reported in individuals with a variety of nonmalignant conditions including: cirrhosis, hepatitis, endometriosis, first trimester pregnancy, ovarian cysts, and pelvic inflammatory disease. Elevated levels during the menstrual cycle also have been reported.
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
<35 U/mL
Interpretation Provides information to assist in interpretation of the test results
In monitoring studies, elevated levels of cancer antigen 125 (CA 125) (>35 U/mL) are a predictor of the presence of intraperitoneal tumor or recurrence. Elevated concentrations have been found in about 72% of patients with surgically proven recurrent ovarian carcinoma. However, normal levels do not rule out recurrence.
A persistently rising CA 125 value suggests progressive malignant disease and poor therapeutic response.
Physiologic half-life of CA 125 is approximately 5 days.
In patients with advanced disease who have undergone cytoreductive surgery and are on chemotherapy, a prolonged half-life (>20 days) may be associated with a shortened disease-free survival.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
Not useful as a screening assay for cancer detection in the normal population.
Results cannot be interpreted as absolute evidence of the presence or absence of disease.
Serum markers are not specific for malignancy and values may vary by method. Values obtained with different assay methods cannot be used interchangeably.
Some individuals have antibodies to mouse protein (HAMA) which can cause interference in immunoassays that employ mouse antibodies. In particular, it has been reported that serum samples from patients who have undergone therapeutic or diagnostic procedures that include infusion of mouse monoclonal antibodies may produce erroneous results in such assays. Rerunning the specimen in question after additional blocking treatment may resolve the issue.
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
1. Devarbhav, H, Kaese D, Williams A, et al. Cancer Antigen 125 in Patients With Chronic Liver Disease. Mayo Clinic Proceedings 2002;77:538-541
2. Sturgeon CM, Duffy MJ, Stenman UH et al: National Academy of Clinical Biochemistry laboratory medicine practice guidelines for use of tumor markers in testicular, prostate colorectal, breast, and ovarian cancers. Clin Chem. 2008 Dec;54:11-79.
3. Sugiyama T, Nishida T, Komai K, et al: Comparison of CA 125 assays with abdominopelvic computed tomography and transvaginal ultrasound in monitoring of ovarian cancer. Int J of Gynaecol Obstet 1996;54:251-256
Method Description Describes how the test is performed and provides a method-specific reference
The instrument used is a Beckman Coulter DXI 800. The Access OV Monitor assay is a two-site immunoenzymatic "sandwich" assay. A sample is added to a reaction vessel along with mouse monoclonal anti-CA 125 antigen alkaline phosphatase conjugate and paramagnetic particles coated with a second mouse monoclonal anti-CA 125 antigen antibody. The CA 125 antigen in the sample binds to the immobilized monoclonal anti-CA 125 antigen on the solid phase, while the conjugate antibody reacts with a different antigenic site on the CA 125 antigen molecule. After incubation in a reaction vessel, materials bound to the solid phase are held in a magnetic field while unbound materials are washed away. Then, the chemiluminescent substrate Lumi-Phos 530 is added to the vessel and light generated by the reaction is measured with a luminometer. The light production is directly proportional to the concentration of CA 125 antigen in the sample. The amount of analyte in the sample is determined from a stored, multi-point calibration curve. (Package insert: OV Monitor Reagent Pack, Beckman Coulter Inc., Brea, CA 2010)
Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.
Monday through Friday; 5 a.m.-12 a.m.
Saturday; 6 a.m.-6 p.m.
Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.
Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result
Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location The location of the laboratory that performs the test
Test Classification Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer's instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR), Investigation Use Only (IUO) product, or a Research Use Only (RUO) product.
CPT Code Information Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Medical Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
86304
LOINC® Code Information Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the result codes returned for this test or profile.
| Result ID | Reporting Name | LOINC Code |
|---|---|---|
| CA25 | Cancer Ag 125 (CA 125), S | 10334-1 |
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