Consider a patient with a very high level of serum antibody…

Consider a patient with a very high level of serum antibody directed against a viral pathogen; determination of the antibody titer using a precipitation assay produces a negative result with 1/2 and 1/4 dilutions of patient serum, but produces a strong result with 1/8 and 1/26 and higher.  This result is related to antibody excess in the patient serum and is referred to as: