Related Experiment Video
Updated: Aug 16, 2026
Accurate and Simple Measurement of the Pro-inflammatory Cytokine IL-1β using a Whole Blood Stimulation Assay
Published on: March 1, 2011
Raised serum prolactin in rheumatoid arthritis: genuine or laboratory artefact?
1Department of Clinical Chemistry, New Cross Hospital, Wolverhampton, West Midlands. WV10 0QP, UK.
Objectives:
Serum prolactin concentrations have been reported as higher, similar or lower in patients with rheumatoid arthritis (RA) compared with control subjects. We investigated whether low biological activity macroprolactin (a prolactin antibody complex), which is detected variably in different prolactin immunoassays, could account for the discrepant total prolactin results reported in RA.
Methods:
We compared serum total prolactin and free prolactin in 60 women with RA and 31 female controls.
Results:
No subject had hyperprolactinaemia or macroprolactinaemia. Serum concentrations of total and free (monomeric) prolactin were higher (P<0.05) in women with RA [mean (s.d.), 225.6 (104.6) and 201.6 (95.4) mU/l respectively] compared with controls [175.0 (68.5) and 154.0 (60.9) mU/l respectively].
Conclusions:
We report higher serum free prolactin concentrations in women with RA compared with control subjects. This result indicates that the higher serum total prolactin levels in patients with RA are the consequence of increased free prolactin concentrations and are not due to macroprolactin.
Insights
Women with rheumatoid arthritis (RA) have higher free prolactin levels compared to controls. This study clarifies that elevated total prolactin in RA patients is due to increased free prolactin, not macroprolactin.
Area of Science:
- Endocrinology
- Immunology
- Rheumatology
Background:
- Conflicting reports exist regarding serum prolactin levels in rheumatoid arthritis (RA) patients.
- Macroprolactin, a prolactin-antibody complex, can interfere with immunoassay results, potentially explaining discrepancies.
Purpose of the Study:
- To investigate if macroprolactin contributes to variable total prolactin measurements in RA.
- To compare serum free and total prolactin concentrations in women with RA and healthy controls.
Main Methods:
- Serum total and free prolactin levels were measured in 60 women with RA and 31 female controls.
- Subjects were assessed for hyperprolactinemia and macroprolactinemia.
Main Results:
- No participants exhibited hyperprolactinemia or macroprolactinemia.
- Women with RA showed significantly higher serum concentrations of both total prolactin (225.6 mU/l vs 175.0 mU/l) and free prolactin (201.6 mU/l vs 154.0 mU/l) compared to controls (P<0.05).
Conclusions:
- Serum free prolactin concentrations are elevated in women with RA.
- The increased total prolactin levels observed in RA patients are attributable to higher free prolactin, not macroprolactin.
More Related Videos
04:50Preliminary Study on Acupuncture Combined with Grain-sized Moxibustion for Treating Rheumatoid Arthritis with Finger Joint Pain
Published on: May 16, 2025
08:32A Pre-Clinical Model of Synovitis Using Ex vivo Human Synovial Tissue with Preserved Function and Architecture
Published on: March 20, 2026