Test ID: PRL
Prolactin, Serum
Secondary ID 
A test code used for billing and in test definitions created prior to November 2011
NY State Approved Indicates the status of NY State approval and if the test is orderable for NY State clients.
Useful For Suggests clinical disorders or settings where the test may be helpful
Aiding in evaluation of pituitary tumors, amenorrhea, galactorrhea, infertility, and hypogonadism
Monitoring therapy of prolactin-producing tumors
Method Name A short description of the method used to perform the test
Immunoenzymatic Assay
Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name
Aliases Lists additional common names for a test, as an aid in searching
Prolactin (PRL)
Prolactin, Serum
Specimen Type Describes the specimen type needed for testing
Specimen Required Defines the optimal specimen. This field describes the type of specimen required to perform the test and the preferred volume to complete testing. The volume allows automated processing, fastest throughput and, when indicated, repeat or reflex testing.
Container/Tube:
Preferred: Serum gel
Acceptable: Red top
Specimen Volume: 0.6 mL
Specimen Minimum Volume Defines the amount of specimen required to perform an assay once, including instrument and container dead space. Submitting the minimum specimen volume makes it impossible to repeat the test or perform confirmatory or perform reflex testing. In some situations, a minimum specimen volume may result in a QNS (quantity not sufficient) result, requiring a second specimen to be collected.
Reject Due To Identifies specimen types and conditions that may cause the specimen to be rejected
| Hemolysis | Mild OK; Gross reject |
| Lipemia | Mild OK; Gross OK |
| Icterus | NA |
| Other | NA |
Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the laboratory. Alternate acceptable temperature(s) are also included.
| Specimen Type | Temperature | Time |
|---|---|---|
| Serum | Refrigerated (preferred) | 7 days |
| Frozen | 90 days |
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Prolactin is secreted by the anterior pituitary gland and controlled by the hypothalamus. It is structurally related to growth hormone (GH), but has few, if any, of the physiological effects of GH. The major chemical controlling prolactin secretion is dopamine, which inhibits prolactin secretion from the pituitary.
The only definitively known physiological function of prolactin is the stimulation of milk production. In normal individuals, the prolactin level rises in response to physiologic stimuli such as sleep, exercise, nipple stimulation, sexual intercourse, hypoglycemia, postpartum period, and also is elevated in the newborn infant.
Pathologic causes of hyperprolactinemia include prolactin-secreting pituitary adenoma (prolactinoma, which is 5 times more frequent in females than males), functional and organic disease of the hypothalamus, primary hypothyroidism, section compression of the pituitary stalk, chest wall lesions, renal failure, and ectopic tumors.
Hyperprolactinemia often results in loss of libido; galactorrhea, oligomenorrhea or amenorrhea, and infertility in premenopausal females; and loss of libido, impotence, infertility, and hypogonadism in males. Postmenopausal and premenopausal women, as well as men, can also suffer from decreased muscle mass and osteoporosis. The latter can sometimes be dramatic in a small subgroup of women who develop severe and acute onset postpartum osteoporosis that remits with cessation of breastfeeding and medical suppression of hyperprolactinemia.
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
Males: 3-13 ng/mL
Females: 3-27 ng/mL
Interpretation Provides information to assist in interpretation of the test results
In males, prolactin levels >13 ng/mL are indicative of hyperprolactinemia.
In women, prolactin levels >27 ng/mL in the absence of pregnancy and postpartum lactation are indicative of hyperprolactinemia.
Clear symptoms and signs of hyperprolactinemia are often absent in patients with serum prolactin levels <100 ng/mL.
Disease states associated with elevated serum prolactin levels include renal failure, untreated hypothyroidism, large nonprolactin-secreting pituitary tumors that have led to pituitary stalk compression, and prolactin-secreting pituitary micro- and macroadenomas.
Mild to moderately increased levels of serum prolactin are not a reliable guide for determining whether a prolactin-producing pituitary adenoma is present, whereas levels >250 ng/mL are usually associated with a prolactin-secreting tumor.
After initiation of medical therapy of prolactinomas, prolactin levels should decrease substantially in most patients; in 60% to 80% of patients, normal levels should be reached. Failure to suppress prolactin levels may indicate tumors resistant to the usual central-acting dopamine agonist therapies; however, a subset of patients will show tumor shrinkage despite persistent hyperprolactinemia. Patient who show neither a decrease in prolactin levels nor tumor shrinkage might require additional therapeutic measures.
Resurgent prolactin levels in patients on long-term therapy indicate, most often, noncompliance with dopaminergic therapy, but can occasionally be an indication of recurrence.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
Multiple medications can cause a rise in serum prolactin level, in particular those that 1) decrease central nervous system (CNS) dopamine levels or block CNS dopamine receptors (antipsychotic drugs, antinausea/antiemetic drugs), or 2) affect CNS serotonin metabolism, serotonin receptors, or serotonin reuptake (anti-depressants of all classes, ergot derivatives, some illegal drugs such as cannabis). In addition, several antihypertensive drugs with high CNS concentrations and central action on catecholaminergic neurons or calcium fluxes can cause hyperprolactinemia, as can opiates, high doses of estrogen or progesterone, and a smattering of other drugs ranging from anticonvulsants (valporic acid) to anti-tuberculous medications (Isoniazid). Collectively, drug effects may account for the majority of mild to modest elevations in prolactin levels (2-4 times upper limit of the reference range). More pronounced prolactin elevations are only occasionally drug-related.
Prolactin levels are regularly transiently elevated after a grand-mal seizure, and also often after petit-mal and atypical seizures. This observation has been clinically leveraged to aid in distinguishing pseudoseizures from true epileptic seizures.
Exercise, stress, and sleep can transiently raise prolactin levels.
High-dose hook effect, leading to false-low serum prolactin measurements, is rarely observed. If a hook effect is suspected because low prolactin results are at variance with clinical presentation, then a dilution must be performed. Contact Mayo Medical Laboratories in this situation.
Prolactin values that exceed the reference values may be due to macroprolactin (prolactin bound to immunoglobulin). Macroprolactin should be evaluated if signs and symptoms of hyperprolactinemia are absent, or pituitary imaging studies are not informative. See MCRPL/87843 Macroprolactin, Serum.
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
Demers LM, Vance ML: Pituitary function. In Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. 4th edition. Edited by CA Burtis, ER Ashwood, DE Bruns. St. Louis, Elsevier Saunders Company, 2006, pp 1976-1981
Method Description Describes how the test is performed and provides a method-specific reference
The instrument used is a Beckman Coulter DXI 800. The Access prolactin assay is a simultaneous 1-step immunoenzymatic sandwich assay. A sample is added to a reaction vessel along with polyclonal goat antiprolactin (anti-PRL)-alkaline phosphatase conjugate, and paramagnetic particles coated with mouse monoclonal anti-PRL antibody. The serum PRL binds to the monoclonal anti-PRL on the solid phase, while the goat anti-PRL-alkaline phosphatase conjugate reacts with a different antigenic site on the serum PRL. After incubation in a reaction vessel, materials bound to the solid phase are held in a magnetic field, while unbound materials are washed away. The chemiluminescent substrate Lumi-Phos 530 is added to the vessel and light generated by the reaction is measured with a luminometer. Light production is directly proportional to the concentration of prolactin in the sample. The amount of analyte in the sample is determined from a stored, multipoint calibration curve. (Package insert: Beckman Coulter Ireland Inc, Ireland, 2010)
Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.
Monday through Friday 5 a.m. – 12 a.m., Saturday 6 a.m. – 6 p.m.
Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.
Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result
Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location The location of the laboratory that performs the test
Test Classification Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer's instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR), Investigation Use Only (IUO) product, or a Research Use Only (RUO) product.
CPT Code Information Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Medical Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
84146
LOINC® Code Information Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the result codes returned for this test or profile.
| Result ID | Reporting Name | LOINC Code |
|---|---|---|
| PRL | Prolactin, S | 2842-3 |
External
link
PDF
document
Excel
document
Word
document