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A B C D E F G H I J K L M N O P Q R S T U V W X Y Z # |
Melatonin, Serum/Plasma
Test Code91899
CPT Codes
83520<br /> This test is not available for New York patient testing.
Preferred Specimen
3 mL plasma collected in an EDTA (lavender-top) tube
Patient Preparation
Fasting is preferred
Minimum Volume
1 mL
Other Acceptable Specimens
Serum
Instructions
Please note: Melatonin concentration varies with light and dark cycle. The concentration is lower during the day and high at night. Patients treated with pituitary or steroid hormones influence the concentration. Hence, it should be discontinued for 2 days prior to the collection of samples.
Transport Temperature
Frozen
Specimen Stability
Room temperature: Not stable
Refrigerated: 24 hours
Frozen: 90 days
Refrigerated: 24 hours
Frozen: 90 days
Methodology
Enzyme Linked Immunosorbent Assay (ELISA) • Extraction
FDA Status
This test was developed and its analytical performance characteristics have been determined by Pan Laboratories. This assay has been validated pursuant to the CLIA regulations. It has not been cleared of approved by the U.S. Food and Drug Administration.
Setup Schedule
Set up: Wed a.m.; Report available: 2-7 days
Reference Range
Day time | 2.0-80.0 pg/mL |
Night time | 18.5-180.0 pg/mL |
Clinical Significance
The pineal gland has been called a neuroendocrine transducer because of its importance in photoperiodism. The major hormone of the pineal gland is Melatonin (N-acetyl-5-methoxy-tryptamine). It is the major indole compound synthesized by the pineal gland. It is converted from Serotonin by Hydroxy Indole-O-Methyl Transferase. It is excreted into the urine as 6-Sulfatoxymelatonin, N-Acetyl Serotonin, other glucuronide and sulfate forms, and also a small amount as unconjugated "free" Melatonin. Melatonin has potent melanocyte contracting properties. Melatonin is primarily secreted during the dark (night) cycle. Levels drop dramatically after exposure to bright light. Melatonin binds to various proteins including Albumin. Patients with cancer frequently have decreased levels of Melatonin as do patients with impaired central nervous system function. Elevated levels can be found in sympathetic orthostatic hypotension. Melatonin has a stimulatory and suppressive feedback on Gonadotropin release depending on Melatonin levels. Altered levels of Melatonin have been reported with sleep disorders, jet lag, depression, stress, schizophrenia, hypothalamic amenorrhea, pregnancy, anorexia nervosa, immunological disorders, as well as sexual maturation during puberty.