You may need a Varicella IGG test, especially if you are at risk for complications, are not immune to VZV, and have symptoms of infection. Speak right away to your healthcare professional if you have an itchy, red, blistering rash all over the body or painful rash that appear in just one area, and along with other symptoms include fever, headache, and sore throat. These symptoms help to diagnose whether you have shingles or chickenpox. You may also undergo this test if you were recently exposed to chickenpox or shingles affected person. One cannot get shingles from another person, but the shingles virus (VZV) can spread and cause chickenpox in people who don't have a proper immune system.