Cancer Antigen (CA) 27.29

CPT Code(s):



Immunochemiluminometric assay (ICMA)






This test is used to manage patients with metastatic carcinoma of the breast.

Specimen Requirements:

Important: Values obtained with different assay methods should not be used interchangeably in serial testing. It is recommended that only one assay method be used consistently to monitor each patient's course of therapy. This procedure does not provide serial monitoring; it is intended for one-time use only.

Type: Serum

Container/Tube: Red-top tube or gel-barrier tube
  • Separate serum or plasma from cells within one hour of collection.

Sample Volume: 1 mL

Minimum Volume: 0.3 mL (Repeat testing is not possible with this specimen volume.)

Storage: Refrigerate specimens immediately after collection.

Stability (collection to time of analysis/testing):

  • Refrigerated: 5 days
  • Frozen: > 1 month
Rejection Criteria:

  • Plasma specimen

Collection Procedure:


Reference Values:

0 - 38.6 units/mL

Interpretation Data:



UFHPL Test #: 68045

UFHPL Epic order code: LAB853

CA 27.29 is a highly polymorphic glycoprotein belonging to the mucin family and is the product of the muc-1 gene. It is most useful using serial measurements to monitor both the course of disease and response to therapy because the direct correlation of changing levels of CA 27.29 with clinical status. In patients with known metastases, a reduction in levels of this marker indicates a good response to treatment while increasing levels indicate resistance to therapy and progressive disease and justify further clinical evaluation and regular monitoring. It has also recently been shown that an elevation of CA 27.29 levels above the upper limit of normal in patients with no clinical evidence of disease is an early indicator of recurrence. An elevated serum CA 27.29 level in patients in remission of stage II or III breast cancer provided a positive predictive value of 83.3% for recurrent disease, with an average lead time of 5.3 months before recurrence was clinically established.


  • Abbate I, Correale M, Musci MD, et al, “Monoclonal Antibody B27.29 Against Mucinous Breast Cancer Associated Antigen CA 27.29 in Breast Cancer,” Br Cancer Res and Treatment, 1991, 19(2):123.
  • Chan DW, Beveridge RA, Muss H, et al, “Use of Truquant BR Radioimmunoassay for Early Detection of Breast Cancer Recurrence in Patients With Stage II and Stage III Disease,” J Clin Oncol, 1997, 15(6):2322-8. PubMed 9196146
  • Hayes DF, Zurawski VR Jr, Kufe DW, “Comparison of Circulating CA 15-3 and Carcinoembryonic Antigen Levels in Patients With Breast Cancer,” J Clin Oncol, 1986, 4:1542-50. PubMed 2428949
  • Linsley PS, Brown JP, Magnani JL, et al, “Monoclonal Antibodies Reactive With Mucin Glycoprotein Found in Sera From Breast Cancer Patients,” Cancer Res, 1988, 48(8):2138-48. PubMed 2450646
  • Reddish MA, Helbrecht N, Almeida A, et al, “Epitope Mapping of Mab B27.29: Within the Peptide Care of the Malignant Breast Cancer Associated Mucin Antigen Coded for by the Human muc 1 Gene,” J Tumor Marker Oncol, 1992, 7:19-27.

Reported Notes: