title: [Macroprolactinemia in the differential diagnosis of hyperprolactinemia].
abstract: BACKGROUND
  Biologically active prolactin and the inactive fraction of macroprolactin can be present in hyperprolactinaemic sera. The reaction of routinely used prolactin assays with macroprolactin is variable.
  
  
  OBJECTIVE
  The present study was undertaken to analyse the leading clinical signs of hyperprolactinemia in macroprolactinemia and true hyperprolactinemia and to assess the prevalence of macroprolactinemia in hyperprolactinemic females.
  
  
  METHODS
  1571 consecutive female patients were investigated for hyperprolactinemia. Prolactin was measured before and after precipitation of macroprolactin by polyethylene glycol in 285 hyperprolactinemic (> 520 mlU/l) patients. Since not a single case of macroprolactinemia (recovery < 40%) was found in the range of 520-700 mlU/l, only in women with prolactin > 700 mlU/l (N = 254) entered the study.
  
  
  RESULTS
  In 59 patients (23%) macroprolactinemia was found. In women, the occurrence of macroprolactinemia increased with advancing age (p < 0.05). "A priori" clinical signs indicating hyperprolactinemia occurred less frequently in patients with macroprolactinemia than in those with true hyperprolactinemia. Pituitary microadenoma was found in 9.8% of macroprolactinemia vs. 31.6% in true hyperprolactinemia (p < 0.01); galactorrhea: 4% in macroprolactinemia vs. 19% in true hyperprolactinemia, (p < 0.05); infertility: 17% in macroprolactinemia vs. 44% in true hyperprolactinemia (p < 0.05). In 8 out of 59 women with macroprolactinemia, true hyperprolactinemia appeared simultaneously (15.3%). Occurrence of polycystic ovaries syndrome was more frequent in the true hyperprolactinemia (12%) that in macroprolactinemia (4.5%).
  
  
  CONCLUSIONS
  It has been shown that macroprolactin does not occur in mild hyperprolactinemia. In women, the occurrence of macroprolactinemia increases with age. "A priori" clinical signs indicating hyperprolactinemia and pituitary abnormality are less frequent in macroprolactinemia than in true hyperprolactinemia. The diagnosis of macroprolactinemia should be used only, when the PRL levels fall to the normal range after precipitation. To avoid diagnostic and therapeutic pitfalls the screening for macroprolactin of all patients with prolactin > 700 mlU/L is recommended.
authors.affiliation: Vas Megye és Szombathely MJV Markusovszky Kórháza, Központi Laboratórium, Szombathely. salamon7@elender.hu
authors.forename: Erzsébet
authors.initials: E
authors.lastname: Toldy
authors.forename: Zoltán
authors.initials: Z
authors.lastname: Löcsei
authors.forename: István
authors.initials: I
authors.lastname: Szabolcs
authors.forename: Pál
authors.initials: P
authors.lastname: Kneffel
authors.forename: Miklós
authors.initials: M
authors.lastname: Góth
authors.forename: Dominika
authors.initials: D
authors.lastname: Szöke
authors.forename: L Gábor
authors.initials: LG
authors.lastname: Kovács
mesh_terms: D000236:Adenoma / Q000150:complications / Q000175:diagnosis*; D000328:Adult; D000367:Age Factors; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D006966:Hyperprolactinemia / Q000097:blood / Q000209:etiology*; D008875:Middle Aged; D010911:Pituitary Neoplasms / Q000150:complications / Q000175:diagnosis*; D011085:Polycystic Ovary Syndrome / Q000150:complications / Q000175:diagnosis*; D011388:Prolactin / Q000097:blood* / Q000737:chemistry; D015203:Reproducibility of Results
chemical_list: C060678:prolactin, polymeric; D011388:Prolactin