Disclosed is a method for detecting Factor D in a diagnostic assay comprising binding an anti-Factor D antibody or an anti-Factor D antigen-binding fragment thereof to Factor D, wherein the antibody comprises: (i) a variable light chain comprising a CDR-L1 having the sequence of SEQ ID NO: 16 a CDR-L2 having the sequence of SEQ ID NO: 17, 21 or 24, and a CDRL3 having the sequence of SEQ ID NO: 18, 19 or 22 and (ii) a variable heavy chain comprising a CDR-H1 having the sequence of SEQ ID NO: 13, 23 or 25 a CDR-H2 having the sequence of SEQ ID NO: 14 and a CDR-H3 having the sequence of SEQ ID NO: 15 or 20, wherein (i) the variable light chain does not comprise the sequence of SEQ ID NO: 2 or (ii) the variable heavy chain does not comprise the sequence of SEQ ID NO: 1.
