123 - Impatto clinico e laboratoristico delle isoforme macromolecolari della prolattina
Rivista: RIMeL - IJLaM, Vol. 1, N. 2, 2005 (MAF Servizi srl ed.)
A.Marcolla, C.Dilberis, F. Dal Bosco, P. Amadori
Clinical and laboratory importance of prolactin macromolecular
isoforms. Macromolecular isoforms of prolactin (PRL) are classified
as BigPRL and BigBigPRL (macroprolactin) on the
basis of their molecular weight. They can be present in
both normoprolactinemic and hyperprolactinemic human
serum, and are detected by current immunometric PRL
assays, causing problems in result interpretation.
The aims of this review were: a) to perform a thorough,
up-to-dated evaluation of the literature on the PRL macromolecular
isoforms and on the ability of immunometric
PRL assays to recognise BigPRL and BigBigPRL isoforms;
b) to define the optimal management of macroprolactinemic
samples.
The results of this survey, show that hyperprolactinemia
due to excess of PRL macromolecular isoforms is as common
as about 20% among blood samples assayed for PRL
in general clinical laboratories, although the rate may vary
according to the method. Gel chromatography is the most
sensitive and specific technique for detecting macroprolactin,
also able of assaying BigPRL, but it is expensive and
time consuming and therefore seldom used. PEG precipitation,
the most employed method to discover BigBig-
PRL, does not enable the recognition of BigPRL. Labs
should routinely perform macroprolactin detection in
hyperprolactinemic samples. Otherwise, information about
the possible presence of macroprolactin should be added
to the report, and the opportunity to check for macroprolactinemia
should be offered. Distinction between BigBigPRL
with and without anti-PRL antibodies is possible
by means of several, non standardised methods, recognising
the immunologic component of the molecule.
However, at present, there is no certain clinical usefulness
in distinguishing between BigBigPRL with or without anti-
PRL antibodies, although future perspectives are reasonably
imaginable.