Macroprolactin Investigations
| Category | Biochemistry >> Endocrinology |
|---|---|
| Test background |
Macroprolactinaemia refers to a polymeric form of prolactin in which several molecules form aggregates with circulating IgG. This rarely elicits a biological response due to the inability of such a large molecule to interact with the prolactin receptor, however, it can be detected by immunoassays leading to spurious elevated prolactin results. Macroprolactin investigations use a PEG precipitation procedure to remove macroprolactin so that the remaining bioactive monomeric form of prolactin can be estimated. |
| Clinical Indications |
Differential diagnosis of macroprolactin-associated hyperprolactinaemia with that of prolactinoma, hypothyroidism or drug/stress-induced hyperprolactinaemia. For samples assayed for total prolactin within NWLP laboratories macroprolactin investigations are automatically added for male patients with total prolactin >450 mU/L and female >600 mU/L. |
| Reference range | Monomeric prolactin reference range: Male <310 mU/L Female <420 mU/L |
| Sample & container required | SST (gold top) or serum (red top) |
| Sample volume | 0.5 mL |
| Transport storage | Stable for 7 days at 2-8°C. Samples can be sent by first class post. |
| Turnaround time | 10 days |