Mycoplasma pneumoniae - IgG

What Does a Positive or Elevated IgG Result Mean?

A positive or elevated IgG result for Mycoplasma pneumoniae indicates:

• You have been previously exposed or infected with the bacterium

• Your body has produced long-lasting antibodies, which may provide partial immunity

• This result does not confirm a current or active infection

This test is most helpful when interpreted alongside IgM results and clinical symptoms to determine whether an infection is recent or resolved.

Common Symptoms of Mycoplasma pneumoniae Infection

• Persistent, dry cough

• Sore throat

• Low-grade fever

• Fatigue

• Chest discomfort

• Headache

• Ear or sinus infections

• In some cases: skin rash, joint pain, or neurological symptoms

Most infections are mild and resolve on their own, but some require antibiotics—especially in children, the elderly, or people with underlying conditions.

Next Steps

• If you are not currently sick, a positive IgG result typically indicates past exposure and does not require treatment.

• If you have symptoms, your provider may order IgM testing or additional respiratory panels to check for active infection.

• Antibiotic treatment (usually macrolides like azithromycin or doxycycline) may be prescribed if an active infection is confirmed.

Summary

The Mycoplasma pneumoniae – IgG test detects antibodies that indicate past exposure or infection with a common cause of atypical pneumonia and other respiratory illnesses. A medium or elevated result suggests your immune system has responded to the bacterium in the past. It is not a marker of active infection by itself and should be interpreted along with your symptoms, medical history, and other test results.

What is Mycoplasma pneumoniae – IgG?

Mycoplasma pneumoniae is a type of bacteria that commonly causes respiratory infections, especially atypical pneumonia—a milder, slower-developing form of pneumonia often referred to as "walking pneumonia." It is also associated with sore throat, prolonged cough, sinusitis, and bronchitis. In some cases, it can contribute to more serious complications such as asthma exacerbations, ear infections, or skin rashes.

The IgG antibody test detects long-term immune response to Mycoplasma pneumoniae. IgG antibodies typically appear several weeks after infection and may remain in the bloodstream for months or even years, indicating past exposure or infection.

What Does a Medium Result Mean?

A medium IgG result reflects a moderate level of antibodies, which may suggest:

• A recent past infection, with IgG levels still stabilizing

• A waning immune response from an older infection

• Borderline reactivity, possibly requiring repeat testing or further evaluation

A medium result alone does not indicate whether the infection is active—it should be considered alongside symptoms and other lab markers, especially IgM.