Laboratory parameters of 1st order – obligatory laboratory tests.
- C1-INH concentration (C1 esterase inhibitor = C1-INH, C1 inhibitor)* .
- C1-INH activity*
- C4
- C1q, CH50, autoantibodies against CH50 – if acquired C1-INH deficiency is suspected.
Laboratory parameters 2nd order – depending on the results of the history, physical examination and obligatory laboratory parameters – for differential diagnostic clarification.
- Gene diagnostics concerning factor XII gene – in case of suspected hereditary angioedema (HAE) type 3 (here C1-INH is normal).
- Family screening
* Hereditary angioedema (HAE; obsolete “hereditary angioneurotic edema”, HANE) – due to C1 esterase inhibitor (C1-INH) deficiency; about 6% of cases:
- Type 1 (85-90% of cases) – decreased activity and concentration of C1 inhibitor.
- Type II (10-15% of cases) – decreased activity with normal or increased concentration of C1 inhibitor.
