As mentioned before, there are no external indications of<unk> , and as such,<unk>  can only be reliably detected by lab tests. The typical tests for complement deficiencies, such as the measurement of C3 and C4, do not detect low levels of the absence of<unk> . These pathways are typically unaltered by any of the three types of<unk> es, but even when they are affected, it is typically within normal levels and is not cause for concern. Instead, histories of infection with anything from the Neisseria genus as well as family history can be indicators, but only specialist centers can screen for<unk> es using immunochemical assays. In particular, the use of ELISA proves to be one of the most effective methods of detecting<unk> , as the average healthy male is expected to show<unk>  antigen levels of around 128.0 ELISA units/ml, and obligate carrier females (recall that<unk>  is an X-linked disease) tend to show an average of 45.6 units/ml. An individual with<unk>  should, by definition, show very little to no<unk>  antigen levels at all, as they do not possess the requisite gene to produce the protein. While<unk> es are rare, they have only been diagnosed in Caucasians, but no other race/ethnicity.
Properdin deficiency
Vitamin K deficiency
Factor I deficiency
Familial isolated vitamin E deficiency
Folate deficiency
Hypodysfibrinogenemia
Factor XIII deficiency
Factor X deficiency