infections
Chickenpox
Diagnosis of Chickenpox
A doctor's evaluation Rarely blood tests and testing of a sample taken from a sore A doctor is usually certain of the diagnosis of chickenpox because the rash and the other symptoms are so typical. Blood tests to measure levels of antibodies in the blood and laboratory tests to identify the virus (usually using a sample scraped from the sores) are rarely needed. ( Antibodies are produced by the immune system to help defend the body against a particular attacker, such as the varicella-zoster virus.) 