For first line testing please refer to C1 esterase inhibitor antigenic testing.
Functional C1 esterase inhibitor is undertaken to screen for hereditary (genetic) or acquired C1 esterase inhibitor deficiency (HAE/AAE).
Patients with Type 2 HAE (approximately 15% of HAE cases) or AAE have low C1 esterase inhibitor function in the presence of normal or high antigenic C1 esterase inhibitor and low C4.
Patients with Type 1 HAE (approximately 85% of HAE cases) can be screened with antigenic C1 esterase inhibitor (see CIN), which will be low, therefore functional testing is not usually required.
Functional C1 esterase inhibitor assay is referred to LabPlus and it is crucial that the sample is separated and FROZEN within 1 HOUR of collection.
OIMM
3.5mL SST or 4ml plain (red topped)
OIMM - contact Immunology immediately
Immunology to centrifuge and separate the sample, freeze serum aliquot before preparing send away.
Sample must be transported to LabPlus FROZEN
FCIN
3 weeks
OIMM