Table 3.

Typical diagnostic laboratory profile of HAE-1 and HAE-2 patients.

	C1–INH function	C1–INH protein level	C4 protein level
HAE-1	↓	↓	↓
HAE-2	↓	N/↑	↓

The most straightforward parameter is the assessment of C1–INH function, which is low in HAE-1 and 2. For daily routine diagnostic purposes, three commercial test kits are available. The read outs are either by chromogenic substrates or the formation of C1–INH–C1s complexes. For apparent C1–INH function the read out matters. Only skilled laboratories can provide correct interpretation of results. In HAE-1 the concentration of the inhibitory protein is low (<50% of the normal mean), while in HAE-2 the concentration is normal or elevated