IgG Subclass Disorders

Causes & Risk Factors

IgG subclass testing is considered based on specific clinical situations, similar to broader immunoglobulin disorder evaluation:

•  Recurrent or unusual infections despite a normal total IgG level on prior testing.

•  Suspected antibody deficiency where a more detailed antibody profile is needed.

•  Family history of primary immunodeficiency.

•  Poor response to standard vaccination in some clinical contexts.

•  As part of a broader immunological work-up for unexplained recurrent infections.

Symptoms & When to Test

IgG subclass disorders can present with a similar infection pattern to broader immunoglobulin deficiency, though some patients may have few or no symptoms.

•  Recurrent infections, particularly respiratory infections (sinusitis, bronchitis)

•  Infections despite a seemingly normal total IgG level

•  Poor response to certain infections or vaccines in some patients

•  Some individuals with subclass deficiency are asymptomatic and identified incidentally

When Should You Consider Testing?

Testing is generally considered in patients with recurrent or unusual infections where total immunoglobulin levels are normal, but clinical suspicion for a subtler antibody deficiency remains, as determined by your doctor.

Why Tests Are Combined

IgG subclass testing is interpreted together with total immunoglobulin levels because a normal total IgG can mask a deficiency in one specific subclass (most often IgG2 or IgG4), meaning subclass testing adds diagnostic value beyond total IgG alone in appropriately selected patients.

Because IgG subclass reference ranges and their clinical significance can vary with age (particularly in children) and because isolated subclass deficiencies do not always cause clinically significant problems, results require careful interpretation alongside the patient's actual infection history and clinical presentation.

Specific antibody assessment (response to specific vaccine antigens) is sometimes added alongside subclass testing for a more functional picture of antibody-mediated immunity, since subclass levels alone do not always predict actual antibody function.

Tests Available at NPL

Most allergy and immunology blood tests do not require fasting. However, some tests ordered at the same time may have specific preparation requirements. Please follow the instructions provided by your doctor or NPL.

Home Sample Collection

NPL offers convenient home sample collection for IgG Subclass Disorders blood tests, so you don't need to visit a lab in person.

→ Book your test online, via the NPL app, or by calling +977 1 5970147 and select a convenient time slot for home sample collection.

→ A certified and experienced NPL phlebotomist visits your home at the scheduled time, following strict hygiene and safety protocols.

→ Your sample is transported under controlled, monitored conditions to NPL's NABL ACCREDITED UNDER ISO15189:2012laboratory for processing.

→ Your digital report is delivered securely to your phone or email, along with access to download and share it as needed.

When to See a Doctor

•  Recurrent infections despite a normal total IgG level

•  Recurrent respiratory infections, particularly sinusitis or bronchitis

•  Suspected antibody deficiency requiring further evaluation

•  Family history of primary immunodeficiency