Clinical
Indications |
|
Macroprolactin is the term used to describe a
complex of serum prolactin with an IgG antibody. This larger form of prolactin has been
recognised for a number of years and is found in some patients with increased serum
prolactin levels. Such patients, on follow-up, have usually been found to show no
characteristics of the hyperprolactinaemic syndrome (infertility, menstrual irregularity,
galactorrhoea). Whereas monomeric prolactin is bioactive,
macroprolactin is considered biologically inactive. The combination of apparent hyperprolactinaemia (due
to macroprolactin) and reduced bioactivity in vivo may cause diagnostic confusion and lead
to inappropriate treatment. Studies have shown that in approximately 15% of
patients with raised serum prolactin the major reactive species was macroprolactin.
Most laboratory assays for prolactin (including that
used at Basildon) measure the prolactin component of macroprolactin. Since macroprolactin
remains in the serum for longer than monomeric prolactin this leads to apparently high
circulating levels of prolactin.
|