After consultation with local immunopathologists, from 10/2/2020 the reference intervals for plasma/serum immunoglobulins IgG, IgA and IgM on children <19 years have been revised. This revision takes into account of recent paediatric reference interval studies and aims to better reflect the physiological state in newborn infants and age related changes up to the age of 18. Reference intervals for adults remain the same. This revision coincided with the change of measurement platform for these tests at LabPlus.
IgG
(g/L)
Newborn to <2 weeks
3.0 - 13.7
>=2 weeks to <6 weeks
1.2 - 6.0
>=6 weeks to <6 months
1.2 - 7.0
>=6 months to <12 months
3.0 - 10.5
>=1 year to <4 years
3.0 - 11.2
>=4 years to <10 years
5.0 - 13.3
>= 10 years to <19 years
6.0 - 15.0
>=19 years to <70 years
7.0 - 16.0
>=70 years
6.0 - 15.0
IgA
(g/L)
Newborn to <1 year
0.09 - 0.39
>=1 year to <3 years
0.19 - 1.09
>=3 years to <6 years
0.29 - 1.69
>=6 years to <14 years
0.3 - 2.4
>=14 years to <19 years
0.4 - 3.1
>=19 years to <70 years
0.8 - 4.0
>=70 years
0.8 - 4.0
| IgM | (g/L) |
|---|---|
| Newborn to <2 weeks | <0.5 |
| >=2 weeks to <13 weeks | 01. - 0.7 |
| >=13 weeks to <1 year | 0.1 - 0.9 |
| >=1 year to <19 years | 0.4 - 1.8 |
| >=19 years to <70 years | 0.4 - 2.5 |
| >=70 years | 0.4 - 2.4 |
IgD 0 - 0.03 g/L (conversion factor 1.412 mg/L - 1 IU/mL)
Uncertainty of Measurement: IgG 4%, IgA 6%, IgM 6%
Test performed on weekdays.
Principle: Immunoturbidometric
Analyser: COBAS
Immunoglobulin levels may be low in patients with congenital and acquired causes of hypogammaglobulinaemia such as X-linked hypogammaglobulinaemia, common variable immunodeficiency, severe combined immunodeficiency and chronic lymphocytic leukaemia. Elevated levels may be seen in patients with infections, autoimmune conditions such as Sjogren's syndrome, liver disease and in paraproteinaemias. IgA deficiency cannot be reliably diagnosed in children less than 5 years of age.
Acute infections may elevate IgG levels to within the reference interval in patients who may have hypogammaglobulinaemia. If this condition is suspected, it is advisable to repeat measurement after resolution of the acute infection.
Serial monitoring of plasma/serum immunoglobulin IgG, A or M should ideally be done through the same laboratory using same measurement system. If cumulative review is attempted on results from different Auckland laboratories, potentially inter-platform difference of up to 40% (for results at or below lower reference limit), 25% (for results within reference limits) and 15% (for results above upper reference limit) can be observed. In patients with paraproteinaemia, even greater between-method differences may be seen.
Emails to chemicalpathologist@adhb.govt.nz will receive priority attention from the on-call chemical pathologist.
If the query concerns a specific patient please include the NHI number in your email.
If email is not a suitable option, please contact the on-call chemical pathologist via Lablink (Auckland City Hospital ext. 22000 or 09-3078995).
Individual chemical pathologists may be contacted but will not be available at all times.
After-hours : contact Lablink (Auckland City Hospital ext. 22000 or 09-3078995) or hospital operator for on duty staff after hours.
Dr Cam Kyle (Clinical Head): CampbellK@adhb.govt.nz ext 22052
Dr Weldon Chiu: WeldonC@adhb.govt.nz ext. 23427
Dr Samarina Musaad: SamarinaM@adhb.govt.nz ext. 22402
Dr Campbell Heron : CHeron@adhb.govt.nz ext. 23427
Dr Sakunthala Jayasinghe : sakunthala@adhb.govt.nz ext. 23427
Dr Owen Yi : wenyiyi@adhb.govt.nz ext. 22045