Macroprolactin on the Advia Centaur: experience with 409 patients over a three-year period.

INTRODUCTION

Macroprolactin (MPRL) is an important source of interference that may lead to misdiagnosis and mismanagement of hyperprolactinaemic patients. Prolactin assays exhibit considerable variation in the detection of MPRL. In this study, we examine the requirement for polyethylene glycol (PEG) precipitation in the analysis of hyperprolactinaemia detected by the Advia Centaur as it has a relatively low reactivity with MPRL.

METHODS

Four hundreds and sixty-four hyperprolactinaemic samples were collected from the laboratory information system for Saint James University Hospital over a three-year period. These samples were screened for MPRL using PEG precipitation protocol. Monomeric prolactin concentration post-PEG precipitation was compared with a reference range determined by PEG precipitation in normal subjects.

RESULTS

MPRL was the cause of hyperprolactinaemia in 4% of patients (16/409) over the three-year period studied. Nine subjects with MPRL also had elevated monomeric prolactin.

CONCLUSIONS

PEG screening is still needed for assays with low MPRL reactivity such as the Advia Centaur and this should be performed with a locally derived reference range for monomeric prolactin.