Extensive Experience and Validation of Polyethylene Glycol Precipitation as a Screening Method for Macroprolactinemia

Macroprolactinaemia: prevalence and aetiologies in a large group of hospital workers

“…Polyethylene glycol treatment precipitates the gamma-globulin fraction and a proportion of less than 40% of total PRL remaining in the supernatant is generally applied as the cut-off to indicate the presence of macroprolactinaemia. 29,31,32 However, in this study we defined macroprolactinaemia as the PEG-precipitated PRL ratio (calculated from total and free PRL values) greater than 57% (mean + 2SD in the 1330 subjects) because the ratio is considered to represent the macroprolactin level directly, that is, it would correlate positively with the macroprolactin level. If the cut-off value is expressed as the proportion of free PRL to total PRL, which would correlate negatively with the macroprolactin level, the value was less than 43% and similar to that reported in other studies.…”

“…If the cut-off value is expressed as the proportion of free PRL to total PRL, which would correlate negatively with the macroprolactin level, the value was less than 43% and similar to that reported in other studies. 29,31,32 The average of 36AE6% precipitated PRL in the majority of serum samples might be because of the nonspecific binding of PRL to PEG or aggregated PRL. 3 Macroprolactinaemia is a different entity from this group and multiple factors are possibly involved in its formation, judging from the widely spread distribution pattern of PEG-precipitated PRL ratio.…”

Recombinant human prolactin for the treatment of lactation insufficiency

“…Prolactin was measured using a 2-site monoclonal nonisotopic system (Axsym; Abbott Laboratories, Abbott Park, Illinois, USA). Development of prolactin antibodies and macroprolactin, a macromolecular complex of monomeric prolactin and an immunoglobulin that retains its immunological activity but not its biological activity, 22 was assessed by measurement of prolactin before and after protein precipitation using polyethylene glycol.…”

“…The increase was not related to macroprolactin, which decreased after treatment with r-hPRL (31AE8 ± 1AE8 vs 29AE6 ± 1AE5%; day 1 vs day 8; P = 0AE03), was similar to placebo (24AE5 ± 4AE6 vs 24AE1 ± 4AE6%; day 1 vs day 8; P = 0AE8) and did not meet the threshold for detection (>60%). 22 Three subjects continued to breast feed for 1 year and 2 stopped at 3-6 months for personal reasons. Four subjects stopped before NICU discharge, including two in the placebo group who did not make milk and two whose milk volume plummeted after stopping r-hPRL.…”

Should macroprolactin be measured in all hyperprolactinaemic sera?

“…Several clinical series have now demonstrated that 15-36% of hyperproalctinaemic sera may be accounted for by the presence of macroprolactin. [6][7][8][9][10][11][12] Two studies have reported how patients who subsequently proved to have macroprolactinaemia were managed during years prior to that diagnosis. 9,13 These studies were possible because of the availability of archived sera.…”