LOINC long common name : Prolactin isoforms panel - Serum or Plasma;
LOINC short name : Prolactin isoforms Pnl SerPl;
LOINC description : The prolactin isoforms panel includes individual tests for monomeric, dimeric, and
macroprolactin, as well as fraction terms for each isomer and an interpretation based
on all of the results. Monomeric prolactin is the most common form of circulating
prolactin. The dimeric form (big-prolactin) has a molecular weight of 50 kD, and
polymeric form (big-big prolactin) has a molecular weight of 150 kD). Big-big prolactin,
known as macroprolactin, and big prolactin are formed in the circulation after secretion
of prolactin from the pituitary. They have a longer half-life than monomeric prolactin
and are not biologically active. However, typical prolactin assays do not differentiate
between the different forms of prolactin, and the presence of big and big-big prolactin
can lead to a false diagnosis of hyperprolactinemia. Methods such as PEG precipitation
can separate macroprolactin and big prolactin from monomeric prolactin in order to
obtain a more accurate measurement of biologically active prolactin, and chromatography
can be used to further characterize the isoforms if necessary. [PMCID: PMC3719302];
Has component