A DNA test is now being used in at least 640 veterinary clinics worldwide to detect lymphoma before a biopsy of the lymph comes back positive, said Anne Avery, VMD, PhD. The test, adapted for use in dogs two years ago by Avery and her colleagues at Colorado State University (CSU), is 85 percent sensitive and 92 percent specific to lymphoma, she said. It is now being tested for use in cats.

Use of the test “provides another piece of the puzzle,” said Kelly Chaffin, DVM, MSpVM, DACVIM, who works at the Animal Diagnostic Clinic in Texas. Veterinarians at the clinic have used the test more than a hundred times to confirm suspected cases of lymphoma or to pinpoint whether a case is a B-cell or a T-cell lymphoma, she said. “For me it completes the whole picture of the case, and may encourage me to continue treatment,” Chaffin added.

Although Avery does not expect the DNA test to affect treatment of lymphoma, if it catches the cancer before it surfaces it may increase survival odds. “Sometimes lymphoma can be hidden,” she said. “This has the potential to save owners a lot of [money on] diagnostic tests and hospital time.”

The test gauges the structure or what Avery calls the “architecture” of the lymph node DNA, and traces derivation of cells. If lymphocytes have unique DNA cancer is present, Avery explained. The test amplifies the CDR3 gene that encodes part of the B-cell (immunoglobulin) or T-cell receptor proteins that bind a pathogen, Avery said. Test samples have ranged from blood and lymph node tissue to an entire foot, she added.

Turnaround time for referrals is about five days, according to Avery, who is currently researching several other utilities for the test.