Sample: Serum 1,0 mL (Fresh)
Units: %R (Recovery)
< 40% Macroprolactimaemia
40 - 50% Indeterminate
> 50% Normal
Serum prolactin circulates in different forms: monomer mPRL, tetramer bPRL and tetramer bbPRL or macroprolactin, (MW > 100 000 kD).
The major form is the monomer mPRL (85-95%) with less than 1% bbPRL. There are some individuals whose sera contain increased amounts of bbPRL, a phenomenon named macroprolactinaemia, but accompanied often by no clinical symptoms directly due to the hormone excess.
Latest evidence indicates that bbPRL is mostly an IgG-mPRL complex. Prolactin-bound IgG has been named Prolactin Autoantibody and it has been suggested that its aetiopathogenesis may be related to the function of prolactin as an in-vivo modulator of cellular and humoral immunity.