Doctors use two types of tests to diagnose chickenpox or shingles:
Antibody: When you're exposed to varicella zoster, your immune system makes proteins to fight it. Your doctor can look for these proteins, called antibodies, in a sample of your blood.
Viral detection: This test can find out if varicella zoster virus is present in the rash. Your doctor can collect samples from unroofed blisters and scabs from blisters that have crusted over.
Your doctor should have the results in 1 to 3 days. You might need to have a second test if the results aren't clear.
Your symptoms and test results will show whether you have shingles. Once you've been diagnosed, you can start on treatment to help you feel better.