Category: Immunoglobulin/ Complement
Test Code: 407
Methodology: Nephelometry
Reference Range: Normal Ranges: Accompanies report (age dependent)
Units: mg/dl
CPT Code: 82787
Schedule / Turnaround Time: Report availability is one week from the time of specimen receipt.
Specimen Requirements:

Specimen need not be refrigerated or frozen. Collect 2-3 ml of blood in a red top or serum separator tube. If possible, separate serum from clot and place into white tube provided with Immco Diagnostics’ collection kits. If separation facilities are not available, the blood can be sent in the tube used for collection.

Sample Stability:

Sample is stable at ambient temperature during shipment. If sample is stored prior to shipment, it is stable refrigerated (2-8°C) up to five days and frozen (-20°C or lower) up to one year.


In normal adults, IgG4 constitutes less than 5% of the total serum immunoglobulins. Elevated IgG4 levels are associated with allergic disease and also seen in asthma, atopic dermatitis and some parasitic diseases. IgG4 elevated at or above 135mg/dl is virtually diagnostic of autoimmune pancreatitis. IgG4 deficiency is frequently associated with chronic and recurrent respiratory infections. It is usually associated with other immunoglobulin deficiencies particularly IgG2 and may be a marker of indefinite but clinically relevant immune disorder.