IgG and IgM Antibody Blood Test: What You Need to Know

This test measures two important antibodies in your blood, immunoglobulin G (IgG) and immunoglobulin M (IgM). Antibodies are proteins your immune system makes to help fight infections, and measuring them can give your doctor valuable information about your health.

The Brucella canis IgG and IgM test is a blood test that detects whether your immune system has produced antibodies against Brucella canis, a bacterium that can spread from dogs to humans. This test helps doctors determine if you have a current or past infection with this bacterium.

IgM is usually the first antibody your body produces when it meets a new infection, so higher levels may suggest a recent or current infection. IgG develops later and often stays in your blood for years, which can point to a past infection or long-lasting immunity.

IgM antibodies are produced first during an infection, usually within 1-2 weeks of exposure. Their presence typically indicates a recent or acute infection. IgG antibodies develop later, usually within 2-4 weeks, and provide long-term immunity. Detecting IgG may indicate a past infection or an ongoing chronic infection.

Your doctor may order this test to find out whether you have a current, recent, or past infection, to check how well your immune system is responding, or to see whether you have developed immunity after an infection or vaccination.

Your doctor may order this test if you have symptoms of brucellosis (such as fever, fatigue, joint pain, or muscle aches) and have recently been exposed to dogs, especially dogs from shelters, breeding facilities, or areas with known Brucella canis outbreaks. Veterinarians, dog breeders, and pet store workers are at higher risk.

A health care professional will draw a small sample of blood from a vein in your arm, usually on the inside of your elbow. The sample is then sent to a laboratory, where specialists measure the amount of IgG and IgM antibodies it contains.

A healthcare professional will draw a blood sample from a vein in your arm. The blood is then sent to a laboratory to test for the presence of IgG and IgM antibodies against Brucella canis.

Your results will show whether IgG or IgM was detected in your blood. Higher IgM levels may suggest a recent infection, while IgG without IgM often means you were exposed in the past. Your doctor will explain your specific values and whether any follow-up testing or treatment is needed.

Results are typically reported as positive or negative for IgG and IgM. A positive IgM result suggests recent infection. A positive IgG result may indicate past exposure or ongoing infection. Your doctor will interpret these results together with your symptoms and exposure history to make a diagnosis.