Varicella Zoster IgG

Varicella Zoster IgG test measures the antibodies which are produced by the immune system in response to varicella zoster infection. Varicella zoster virus (VZV) belongs to the herpes virus family and causes chickenpox and shingles.

This test may be performed to detect and diagnose a current or past infection with VZV. Usually, the infection can be predicted from the clinical signs and symptoms but in few people who have atypical skin lesions, this test is helpful to confirm the infection.

This test is used to diagnose a current infection or to determine any developed immunity from prior infection or by vaccination in pregnant women or patients who have undergone an organ transplant.

VZV can cause chickenpox in people who have not been vaccinated or previously exposed. The initial or primary infection is highly contagious. It can pass from one to another via coughing or sneezing or touching fluid from blisters. 

The signs and symptoms of primary infection include rash which is itchy and it emerges after about 2 weeks of exposure to the virus. It is followed by the formation of vesicles which are pimple-like papules that become small, fluid-filled blisters. These vesicles break, form a crust, and then heal. Several hundred vesicles go through this process over a few days.

The virus becomes inactive (dormant/not yet manifesting the usual symptoms) as the primary or initial infection resolves, but it lives in sensory nerve cells. The affected individual develops antibodies during the infection which helps in prevention of developing chickenpox again. 

The virus can get activated again in individuals who have a weak immune system. The virus migrates down the nerve cells to the skin, causing shingles which is also known as herpes zoster. The symptoms of shingles include a mild to intense burning or itching pain in face, band of skin at the waist, or any other area on the body. One may experience pain, itching, tingling, rash with or without vesicles at the affected areas after several days of infection from the virus. Within a few weeks, the rash and pain subside in few people and the virus again becomes inactive. 

Most cases resolve without complications but people with weakened immune systems like those who have HIV/AIDS or organ transplant recipients, the disease can have more severe and long-lasting effects. In some cases, the virus may spread to the central nervous system. 

The effects of exposure to VZV in case of pregnant women on a developing baby or newborn depends on the occurrence of the infection or any previous exposure of the mother to the infection. During the first 20 to 30 weeks of pregnancy, a primary VZV infection rarely causes congenital abnormalities in the unborn baby. Whereas, if the infection occurs in 1 to 3 weeks before delivery then the baby might get born with chickenpox or might acquire it after birth. The infection can be fatal if the baby does not have maternal antibody protection.