Historically, physicians look for remaining thyroid cells either by having patients take radioactive iodine, which concentrates in the thyroid gland and can be detected by scanners, or by analyzing blood for thyroglobulin, a protein made by thyroid cells. Physicians need both methods to pick up leftover thyroid cells that could be cancerous. Those under treatment and scheduled for monitoring must therefore stop taking their thyroid hormone pills. Patients become generally miserable for two or three weeks, Levine says. The new test solves the problem.
Patients can stay on their thyroid medicine.
Based on the presence of genes for thyroglobulin, rather than on thyroglobulin itself, the test uses PCR to amplify very low-level gene activity the sort you d find with stray cells to the point where it can be detected. The technique is extremely sensitive. It can tell, indirectly, if just one or two thyroid cells exist in a teaspoonful of blood, Levine says.