Specimens collected at Auckland hospital:
All specimens requiring the C1 esterase inhibitor functional assay should only be collected between 8am AND 2.30pm MON - FRI.
At the time of collection, place an "Urgent" label on the form and indicate below the sticker "C1 Esterase". Contact ICHEM on 09 307 49 49 ext 22113 to inform the laboratory of the collect.
It is crucial the sample is separated and frozen within 1 hour of collection.
Specimen Collected at offsite and sent to Labplus:
Please spin and separate within 1 hour of collection.
Prepare 2 aliquots and freeze specimen.
Place the yellow fluorescent sticker Urgent C1 Esterase Inhibitor label on the form.
Ensure the yellow sticker is visible when form is placed in the biohazard bag. Transport frozen.
C1 inhibitor levels are reduced in cases of hereditary angioedema. In this condition, 85% of patients will have decreased antigenic and functional C1 inhibitor levels, whereas 15% will have a dysfunctional protein (normal or high antigenic assay, low functional assay).
The C4 component of complement is almost invariably low in cases of hereditary angioedema, and C2 is low during acute attacks.
C1 Esterase Inhibitor deficiency causes angioedema. The C1 Esterase Inhibitor deficiency may be genetic (hereditary angioedema) or aquired. Hereditary angioedema may be caused by an absence or a dysfunctional C1 Esterase Inhibitor. Most patients with C1 Esterase Inhibitor deficiency have reduced C4 levels. A normal C4 level makes C1 Esterase Inhibitor deficiency unlikely. Note that patients with type 3 HAE may have normal C4 levels.
Acquired C1 inhibitor deficiency can occur rarely in SLE and B cell lymphomas. Acquired C1 inhibitor deficiency can be distinguished from the hereditary form by measuring C1q levels which are low in the acquired form but normal in the inherited.
All requests sent to LabPLUS for a C1 Esterase Inhibitor level will receive a C4 assay. The laboratory does not perform a functional C1 Esterase Inhibitor assay routinely unless specifically requested. If you suspect C1 Inhibitor deficiency please contact Associate Professor Rohan Ameratunga.
For further information contact the laboratory (09) 307 4949 ext 22000 or:
Associate Professor Rohan Ameratunga , Immunopathologist: Locator 93-5724
Or the LabPLUS Immunology Team
Specimens collected at Auckland hospital:
All specimens requiring the C1 esterase inhibitor functional assay should only be collected between 8am AND 2.30pm MON - FRI.
At the time of collection, place an "Urgent" label on the form and indicate below the sticker "C1 Esterase". Contact ICHEM on 09 307 49 49 ext 22113 to inform the laboratory of the collect.
It is crucial the sample is separated and frozen within 1 hour of collection.
Specimen Collected at offsite and sent to Labplus:
Please spin and separate within 1 hour of collection.
Prepare 2 aliquots and freeze specimen.
Place the yellow fluorescent sticker Urgent C1 Esterase Inhibitor label on the form.
Ensure the yellow sticker is visible when form is placed in the biohazard bag. Transport frozen.
All C1 Esterase requests also require a separate aliquot for C4 to prevent erroneous results for the C1 Esterase assay due to repeated freeze/thawing.