Category: Immunoglobulin/ Complement
Test Code: 400
Methodology: Nephelometry
Reference Range: Normal Range: Accompanies report (age dependent).
CPT Code: 83883
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, IgG constitutes approximately 75% of the total serum immunoglobulins. The majority of IgG is synthesized in plasma cells, and its ability to cross the placenta gives it a crucial protective role in the first weeks of life when the neonatal immune system is not fully developed. Elevated IgG levels are associated with chronic liver disease and myeloma; reduced levels may be associated with malignancy and other severe protein losing conditions. Normal serum levels vary with age and race.