CA 27.29 Test
Synonyms
Truquant BR
Purpose
The CA 27.29 Test is a blood test that measures the level of cancer antigen 27.29, a protein often found in higher amounts in individuals with breast cancer.
The test helps with monitoring treatment effectiveness in breast cancer patients, detecting recurrence of breast cancer after initial treatment, and assessing disease progression, especially in metastatic cases.
To improve diagnostic accuracy and patient management, the test may be done alongside, CA 15-3 test, mammography or breast ultrasound, biopsy, hormone receptor testing, complete blood count (CBC), and liver function tests (LFTs).
Patient Preparation
No special preparations required.
Samples
1ml with a minimum volume of 0.3ml of serum collected in a red top tube or gel barrier tube. Transfer the separated serum into a plastic transport tube if you use a red-top tube, and then refrigerate the samples.

Reference Range
0-38.6 units/ml
Results Turnaround
Within 24 hours of receipt of samples.
Diseases / Diagnostic indicators
The CA 27.29 Test is commonly associated with the evaluation of metastatic breast cancer. Elevated CA 27.29 levels are often found in individuals with advanced or spreading (metastatic) breast carcinoma.
Here are some possible outcomes of the test
High CA 27.29 levels may indicate:
- Active or recurring breast cancer
- Cancer spreads to other parts of the body (metastasis).
In rare cases, elevated levels may also appear in other cancers (e.g., lung, liver, ovarian) or benign conditions like liver disease or fibrocystic breast changes.
Normal or low levels may suggest:
- A successful response to treatment.
- No active disease.
- Early-stage cancer does not release detectable antigen levels.
For more on the CA 27.29 testing, read this study.