Lab Test


Test Codes

Antrim #17232, EPIC: LAB5104, SOFT: PROL

Specimen Collection Criteria

Collect: One Gold-top SST tube. (Minimum Whole Blood: 4.0 mL)

Contact the Laboratory for acceptability of other tube types.

Physician Office/Draw Specimen Preparation

Let SST specimens clot 30-60 minutes then immediately centrifuge to separate serum from cells. Refrigerate (2-8°C or 36-46°F) the centrifuged SST tube within two hours of collection.

Preparation for Courier Transport

Transport: Centrifuged SST tube, refrigerated (2-8°C or 36-46°F). (Minimum: 1.0 mL)

Rejection Criteria

Red-top tubes with serum not separated from cells within two hours of collection. 

In-Lab Processing

Let SST specimens clot 30-60 minutes. Centrifuge SST tubes or Microtainers® to separate serum from cells. Deliver immediately to the appropriate testing station.


Specimen Stability for Testing:

Centrifuged SST Tubes and Microtainers® with Separator Gel
Room Temperature (20-26°C or 68-78.8°F): 2-4 hours
Refrigerated (2-8°C or 36-46°F): 7 days
Frozen (-20°C/-4°F or below): Unacceptable

Red-top Tubes and Microtainers® without Separator Gel
Room Temperature (20-25°C or 68-77°F): 2-4 hours
Refrigerated (2-8°C or 36-46°F): Unacceptable
Frozen (-20°C/-4°F or below): Unacceptable

Serum Specimens (Pour-Overs)
Room Temperature (20-26°C or 68-78.8°F): 2-4 hours
Refrigerated (2-8°C or 36-46°F): 7 days
Frozen (-20°C/-4°F or below): 7 days

Specimen Storage in Department Prior to Disposal:

Refrigerated (2-8°C or 36-46°F): 7 days


Farmington Hills Chemistry Laboratory
Royal Oak Automated Chemistry Laboratory


Sunday – Saturday, 24 hours a day.
Results available within 24 hours of receipt in the Laboratory.

Reference Range

Males:  2.0-18.0 ng/mL.
Non-Pregnant Females:  3.0-30.0 ng/mL.
Post-Menopausal Females:  2.0-20.0 ng/mL.
Pregnant Females:  10.0-208 ng/mL. 

Test Methodology

Chemiluminescence Immunoassay.


  • Prolactin levels are elevated at birth and decline to adult levels in less than three months.
  • Women have slightly higher mean prolactin levels than men. They have a slight rise at puberty, apparently estrogen related and a corresponding fall at menopause. During pregnancy, the prolactin level climbs steadily to ten or twenty times its former value, then drops back to normal after delivery, within three weeks in non-nursing mothers. In those mothers who breast-feed, the decline to normal is more gradual. Women taking oral contraceptives or estrogen treatment may have prolactin levels higher than normal.
  • Prolactin is a stress hormone. Surgery, venipuncture or a clinical interview have been reported to cause a transient rise in prolactin. The release of prolactin is episodic. There may be day-to-day fluctuations with CV's as high as 30%. There is also a sleep-related diurnal variation. Prolactin levels increase during sleep and reach their lowest a few hours after waking.

Clinical Utility

Prolactin levels aid in the diagnosis of pituitary tumors, amenorrhea, galactorrhea, infertility, and hypogonadism. Prolactin levels aid in monitoring therapy of prolactin-producing tumors. Prolactin values greater than 200 ng/mL usually indicate prolactinomas. For most other causes listed above Prolactin values are less than 200 ng/mL.

CPT Codes



Last Updated


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UroVysion® is a registered trademark of Abbott Laboratories. ThinPrep® is a registered trademark of Hologic, Incorporated.


This directory currently reflects information only for specimens collected and/or processed at the
Farmington Hills, Grosse Pointe, Royal Oak, and Troy campuses.