Carcinoembryonic Antigen In Serum/plasma

Indications

frequency of elevated of CEA levels is higher in patients with active malignancy than those in remission

The IMx CEA assay is a Microparticle Enzyme Immunoassay (MEIA) for the quantitative measurement of Carcinoembryonic Antigen ( CEA) in serum or plasma. The IMx CEA assay is used as an adjunctive test in predicting prognosis & as an aid in the management of cancer patients in whom changing concentrations of CEA are observed.
The IMx CEA reagents & samples are added to the reaction cell in the following sequence:

The probe/ electrode assembly delivers the sample, the specimen diluent & Anti- CEA Coated microparticles into the incubation well of the reaction cell.
An aliquot of the reaction mixture is transferred to the glass fiber matrix. The microparticles bind irreversibly to the glass fiber matrix.
The matrix is washed to remove unbound materials.
The Anti- CEA: Alkaline Phosphatase Conjugate is dispensed onto the matrix & binds to the antibody- antigen complex.
The matrix is washed to remove unbound materials.
The substrate, 4-Methylumbelliferyl Phosphate, is added to the matrix & the fluorescent product is measured by the MEIA optical assembly.

Clinical studies indicate that CEA, although originally thought to be specific for digestive tract cancers may also be elevated in other malignancies & in some nonmalignant disorders including smoking, renal disease & gastritis.
CEA testing can have significant value in the monitoring of patients with diagnosed malignancies in whom changing concentrations of CEA are observed. A persistent elevation in circulating CEA following treatment is strongly indicative of occult metastatic &/or residual disease. A persistently rising CEA value may be associated with progressive malignant disease & a poor therapeutic response. A declining CEA value is generally indicative of a favorable prognosis & a good response to treatment. Patients who have low pretherapy CEA levels may later show elevations in the CEA level as an indication of progressive disease.
Clinical relevance of the CEA assay has been shown in the follow- up management of patients with colorectal, breast, lung, prostatic, pancreatic, & ovarian carcinoma. Follow-up studies of patients with colorectal, breast, & lung carcinoma suggest that the preoperative CEA level has prognostic significance.
Cerebrospinal fluid ( CSF) levels may be useful for establishing the presence of primary or metastatic central nervous system disease.

Serum or plasma may be used with the IMx CEA assay. When serial samples are being evaluated, the same type of specimen should be used throughout the study.
If the assay is to be performed within 24 hours after collection, the specimen should be stored in the refrigerator at 2-8 C. If the testing will be delayed more than 24 hours, the specimen should be frozen. Mix thoroughly after thawing to ensure consistency in the results. Avoid repeated freezing & thawing.
Specimens showing particulate matter, erythrocytes, or turbidity should be centrifuged before testing.

SAMPLE : 150 uL of specimen is the minimum volume required to perform the assay.

Abbott Laboratories ,Diagnostic Division ,Abbott Park, IL 60064 Tumor Markers, IMx CEA, OCTOBER 1991.
IMx System Operation Manual, Abbott Diagnostics, a Division of Abbott Laboratories, Abbott Park, IL. 60064, AUGUST 1988.
IMx System Assay Manual, Abbott Diagnostics, a Division of Abbott Laboratories, Abbott Park, IL. 60064, AUGUST 1988.