[Macroprolactinemia in the differential diagnosis of hyperprolactinemia].
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.
Toldy
Erzsébet
E
Vas Megye és Szombathely MJV Markusovszky Kórháza, Központi Laboratórium, Szombathely. salamon7@elender.hu
Löcsei
Zoltán
Z
Szabolcs
István
I
Kneffel
Pál
P
Góth
Miklós
M
Szöke
Dominika
D
Kovács
L Gábor
LG
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
C060678:prolactin, polymeric; D011388:Prolactin