Telomeres are protective caps that cover the tips of the body�s chromosomes, similar to the plastic tips that are at the end of a shoelace. The telomeres tend to become shorter as people age, so testing the telomeres is a way to look at cellular aging. The shortness of the telomeres points to the patient�s biological age and is actually measured using the patient�s white blood cells taken with a blood sample for this specially designed test. After many cell divisions in a person�s life, once the telomeres shorten to a critical point the cell is no longer able to divide and thusly, dies.