Turnaround times
The quoted turnaround time is from sample receipt in the laboratory, to results authorisation in the Laboratory Information Management system. The times do not include transport of specimen to the laboratory or the administrative process to print and post/email reports. Service users must allow for transport and reporting time when ordering tests.
Clinical background:
Measurement of IgG subclasses is only indicated as follows:In the investigation of suspected primary immunodeficiency, after discussion with an immunologist (adult or paediatric).
In the diagnosis of suspected Sjogren’s syndrome, where the polyclonal increase in IgG is restricted to IgG1.
In the diagnosis of IgG4-related autoimmune diseases.
Specimen container paediatric:
Serum-Plain tube
Specimen container adult:
Serum-SST
Minimum volume paediatric:
2 ml
Minimum volume adult:
2 ml
Special requirements:
None
Sample stability:
Stored for 1 year at -80 degrees. Samples should not be freeze thawed prior to testing
Freq analysis:
Weekly
Add on test:
Cannot be added on due to stability issues. Please discuss with the Protein Laboratory
Quality assurance:
UK NEQAS for IgG SUBCLASSES, IMMPROVE Subclass Quality Assurance
Interpretation:
Low levels are associated with HAE. However due to stability of C1 esterase inhibitor low levels should be discussed with Immunology
Reference ranges:
Reference ranges:
| Age range (years) | IgG1 (g/L) | IgG2 (g/L) | IgG3 (g/L) | IgG4 (g/L) |
| 0 to 2 | 1.94 – 8.42 | 0.225-3.0 | 0.186-0.853 | 0.005-0.784 |
| 2 to 4 | 3.15 – 9.45 | 0.36 – 2.25 | 0.173-0.676 | 0.001-0.537 |
| 4 to 6 | 3.06 – 9.45 | 0.605-3.45 | 0.099-1.221 | 0.018-1.125 |
| 6 to 8 | 2.88 – 9.18 | 0.44 – 3.75 | 0.155-0.853 | 0.004-0.992 |
| 8 to 10 | 4.32 – 10.20 | 0.72 – 4.30 | 0.127-0.853 | 0.019-0.932 |
| 10 to 12 | 4.23 – 10.60 | 0.76-3.5 | 0.173-1.730 | 0.016-1.15 |
| 12 to 14 | 3.42 – 11.50 | 1.00 – 4.5 | 0.283 – 1.25 | 0.037-1.360 |
| 14 to 16 | 3.15 – 8.55 | 0.64 – 4.95 | 0.23 – 1.96 | 0.11 – 1.57 |
| >16 | 3.4 – 10.3 | 1.1 – 9.1 | 0.17 – 1.7 | 0.03 – 1.1 |
Please note update to reference range 01/06/2022