UCSF Navigation Bar

UCSF Departments of Pathology & Laboratory Medicine Home Page

Lab Manual for UCSF Clinical Laboratories

Lab Manual for SFGH

Internal Resources

PROLACTIN, SERUM

Item Value
Available Stat? No
Test code PRL
Performed by? Chemistry
Sendout? no
Price range $$$
In House Availability Mon - Fri
Sat & Sun (12 pm - 8 pm)
Principle The Siemens Centaur assay is a two-site sandwich immunoassay using direct chemiluminometric technology.
Interpretation Prolactin is a glycoprotein hormone secreted by the anterior pituitary gland. Under the influence of estrogens and progestins, prolactin is involved in the initiation and maintenance of lactation. The following causes of elevated prolactin levels are recognized:

1. pituitary microadenoma, commonly associated with galactorrhea, amenorrhea or infertility;

2. pituitary macroadenoma;

3. chronic renal failure;

4. pregnancy;

5. breast stimulation or chest wall trauma;

6. primary hypothyroidism;

7. empty sella syndrome;

8. idiopathic;

9. hypothalamic states;

10. drugs:

a. dopaminergic-blocking agents, such as: phenothiazines,
butyrophenones, and benzamides;

b. dopamine-depleting agents: alpha-methyldopa, reserpine;

c. Noncatecholamine-dependent agents: thyrotropin - releasing hormone,
estrogens.
Container type gold top gel tube
Amount to Collect 2 mL
Collection Instructions Plasma samples cannot be assayed.
Sample type Blood
Normal range
Men: 2.1-17.7 mcg/L*

Women:
non-pregnant: 2.8-29.2 mcg/L*
pregnant: 9.7-208.5
post-menopausal: 1.8-20.3


*Units are referenced to 3rd International Reference Preparation (3rd IRP), IS 84/500.
Stability Serum stable 48 hrs at 2-8°C;
2 weeks frozen at -20°C.
Interferences 1. Auto- (rheumatoid factor) and heterophile antibodies in human serum can react with reagent immunoglobulins, interfering with in vitro immunoassays. Patients routinely exposed to animals or to animal serum products can be prone to this interference. Anomalous values may be observed. The most common, although not exclusive, interference seen in immunometric ("two-site," "sandwich") assays is a spuriously high value. Results inconsistent with clinical findings or previous laboratory values can be investigated by the laboratory for this phenomenon. Call the Clinical Chemistry Laboratory Medicine Resident (x65527, pager 415-443-2311).

2. A paradoxical, false low result may rarely occur when patient samples with extremely high concentrations of peptide/protein analytes (e.g. AFP, hCG, PSA, etc.) are measured by immunometric ("two-site," or "sandwich") assays. For example, a true value of 3,000,000 U/L could be reported as < 5 or 21 U/L. This phenomenon is called the "high dose hook effect." Results inconsistent with clinical findings or previous laboratory values can be investigated by the laboratory for this phenomenon. Call the Clinical Chemistry Laboratory Medicine Resident (x65527, pager 415-443-2311).

3. Macroprolactin is a circulating, heterogeneous, high-molecular weight form of prolactin that has variable cross-reactivity in different immunoassays. The bioactivity of macro-prolactin is under debate, but it appears that a "pseudo-hyperprolactinemia" caused by macroprolactin does occur in some patients who are asymptomatic or whose symptoms cannot be attributed to a prolactinoma/other clearly defined etiologies. This assay (Advia Centaur) has been categorized in several studies as having infrequent and low cross-reactivity to macroprolactin. However, some cases of increased prolactin due primarily to cross-reactivity of macroprolactin in the Centaur assay have been described. For more information, call the Clinical Chemistry Laboratory Medicine Resident (x65527, pager 415-443-2311).
References 1. Tietz, N.W. Textbook of Clinical Chemistry and Molecular Diagnosis, ed. 4. St. Louis, MO: Elsevier Saunders, 1976-1981; 2006.

2. Bayer 111746 Rev. E, 5/2000. Siemens Medical Solutions Diagnostics, Malvern, PA.
CPT coding 84146
Last Updated 10/23/2012 4:33:24 PM
Search Our Test Menu
UCSF home page UCSF home page About UCSF Search UCSF UCSF Medical Center