Melatonin
Test Mnemonic
MELAT
CPT Codes
- 83520 - QTY (1)
Aliases
- N-acetyl-5-methoxy-tryptamine
- Sleep hormone
Performing Laboratory
Quest SJC
Specimen Requirements
| Volume | Type | Container | Collect Temperature | Transport Temperature | Special Instructions |
|---|---|---|---|---|---|
| 3 mL | Plasma | EDTA (Lavender) | Frozen | Draw 2 tubes to ensure adequate volume. Patient Prep: Fasting specimen preferred. 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; should be discontinued for 2 days prior to collection. Centrifuge, aliquot plasma into standard aliquot tube and freeze. |
Alternate Specimen Requirements
| Volume | Type | Container | Collect Temperature | Transport Temperature | Special Instructions |
|---|---|---|---|---|---|
| 3 mL | Serum | SST (Gold) | Frozen | Draw 2 tubes to ensure adequate volume. Patient Prep: Fasting specimen preferred. 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; should be discontinued for 2 days prior to collection. Centrifuge, aliquot serum into standard aliquot tube and freeze. | |
| 3 mL | Serum | No additive (Red) | Frozen | Draw 2 tubes to ensure adequate volume. Patient Prep: Fasting specimen preferred. 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; should be discontinued for 2 days prior to collection. Centrifuge, aliquot serum into standard aliquot tube and freeze. |
Minimum Specimen Requirements
| Volume | Type | Container | Collect Temperature | Transport Temperature | Special Instructions |
|---|---|---|---|---|---|
| 1 mL |
Stability
| Environmental Condition | Description |
|---|---|
| Ambient | Unstable |
| Frozen | 90 days |
| Refrigerated | 24 hours |
Days Performed
Wed
Turnaround Time
3 - 8 days
Methodology
| Name | Description |
|---|---|
| Enzyme-Linked Immunosorbent Assay (ELISA) | |
| Extraction (EXT) |
Reference Range
| Melatonin | |||||
|---|---|---|---|---|---|
| Sex | Age From | Age To | Type | Range | Range Unit |
| Day time: 2.0 - 80.0 pg/mL | Night time: 18.5 - 180.0 pg/mL |
Special Info
Patient Prep: Fasting specimen is preferred. 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; should be discontinued for 2 days prior to collection.
Clinical Info
The pineal gland is considered 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 (CNS) 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.