The UCLA School of Medicine performs several laboratory tests for the differential diagnosis of A-T. These tests are performed in a CLIA-certified laboratory within the Department of Pathology’s Diagnostic Molecular Pathology Laboratory. The tests must be ordered by a physician, and results will be returned to that physician or a genetic counselor working with the physician.
Colony Survival Assay (CSA) for radiation sensitivity
This test requires a sample of 5-10 ml heparinized blood, to arrive within 3 days with no refrigeration. The sensitivity of the test is >99%, with a specificity of >93% (see Sun et al., J Pediatr 2002 140:724-31). CSAs take approximately 12 weeks to complete. Please note that when CSAs are performed for various research protocols, the tests may take longer to complete.
Western blot to detect the presence of ATM protein
This test is performed using the cell line established for the CSA. Results of the Western blot are usually ready by the time the CSA is complete (approximately 12 weeks) and serve as additional confirmation of the diagnosis.
A single charge of $1,065 is made for both the CSA and the Western. Most insurance carriers will pay for this testing.
Haplotyping for prenatal testing
This test requires a blood sample from the amnion (fetal tissue), as well as blood samples from the previously affected child, all available siblings, mother and father. The diagnosis of A-T for the previously affected child must have been firmly documented by either CSA or Western blot (preferably both), as well as by a clinical summary provided by the referring physician. If specific ATM gene mutations are known at the time of haplotyping, tests for these mutations are performed in parallel. It is preferred that haplotyping be completed on the family members prior to the mother’s pregnancy. This effectively decreases the time it takes to obtain the results once the amniotic sample is received. The cost of haplotyping is $750/family.
At present, carrier testing and sequencing of the ATM gene (to determine new mutations that cause A-T) are not performed for clinical purposes by our laboratory.
For laboratory order forms and CPT insurance codes for CSA/Western and haplotyping, please call 310-825-7200.