Cortisol, Saliva (SALCT)

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Marshfield Clinic Public WebSite

Test Code: CTSALSO

Overview
Ordering
Specimen
Performing
Clinical/Interpretive
Contacts
Coding

Synonyms/Keywords

Nighttime Salivary Cortisol, Salivary Cortisol, Salivary Cushings, Salivary Hydrocortisone

SA CTSALSO

Useful For

Screening for Cushing syndrome

Diagnosis of Cushing syndrome in patients presenting with symptoms or signs suggestive of the disease

Specimen Requirements

Specimen Type	Preferred Container/Tube	Acceptable Container/Tube	Specimen Volume	Specimen Minimum Volume (allows for 1 repeat)	Pediatric Minimum Volume (no repeat)
Saliva	SARSTEDT Salivette		1.5 mL	0.6 mL

Collection Processing Instructions

1. Do not brush teeth before collecting specimen.

2. Do not eat or drink for 15 minutes prior to specimen collection.

3. Collect specimen between 11 p.m. and midnight, and record collection time.

4. To use the Salivette:

a. Remove top cap of container to expose swab.

b. Place swab directly into mouth by tipping container so swab falls into mouth. Do not touch swab with fingers.

c. Keep swab in mouth for approximately 2 minutes. Roll swab in mouth, do not chew swab.

d. Place swab back into its container without touching, and replace the cap.

e. Record collection time, and send appropriately labeled Salivette to laboratory.

Additional Information:

1. Reference values are also available for 8 a.m. (7 a.m.-9 a.m.) and 4 p.m. (3 p.m.-5 p.m.) collections, however, 11 p.m. to midnight collection is preferred.

2. Indicate collection time.

3. If multiple specimens are collected, submit each vial under a separate order.

Return to testing laboratory promptly following collection.

Specimen Stability Information

Specimen Type	Temperature	Time
Saliva	Refrigerated (preferred)	28 days
	Frozen	60 days
	Ambient	28 days

Rejection Criteria

All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.

Interference

Acute stress (including hospitalization and surgery), alcoholism, depression, and many drugs (eg, exogenous glucocorticoids, anticonvulsants) can obliterate normal diurnal variation, affect response to suppression/stimulation tests, and cause elevated cortisol levels.

Cortisol levels may be increased in pregnancy and with exogenous estrogens.

Midnight salivary cortisol assay cannot diagnose hypocortisolism or Addison disease because of the limited sensitivity of the assay method.

Performing Laboratory Information

Performing Location	Day(s) Test Performed	Report Available	Methodology/Instrumentation
Mayo Clinic Laboratories	Monday, Wednesday, Friday	2 to 4 days	Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)

Reference Lab

Mayo Clinic Laboratories

Test Information

Cortisol levels are regulated by adrenocorticotropic hormone (ACTH), which is synthesized by the pituitary in response to corticotropin-releasing hormone (CRH). Cushing syndrome results from overproduction of glucocorticoids as a result of either primary adrenal disease (adenoma, carcinoma, or nodular hyperplasia) or an excess of ACTH (from a pituitary tumor or an ectopic source). ACTH-dependent Cushing syndrome due to a pituitary corticotroph adenoma is the most frequently diagnosed subtype; most commonly seen in women in the third through fifth decades of life.

CRH is released in a cyclic fashion by the hypothalamus, resulting in diurnal peaks (elevated in the morning) and nadirs (low in the evening) for plasma ACTH and cortisol levels. The diurnal variation is lost in patients with Cushing and these patients have elevated levels of evening plasma cortisol. The measurement of late-night salivary cortisol is an effective and convenient screening test for Cushing syndrome.(1) In a recent study from the National Institute of Health, nighttime salivary cortisol measurement was superior to plasma and urine free cortisol assessments in detecting patients with mild Cushing syndrome.(2) The sensitivity of nighttime salivary cortisol measurements remained superior to all other measures. The distinction between Cushing syndrome and pseudo-Cushing states is most difficult in the setting of mild to moderate hypercortisolism. Subtle increases in salivary cortisol at the midnight cortisol (cortisol of nadir) appear to be 1 of the earliest abnormalities in Cushing syndrome.

Reference Range Information

7 am - 9 am : 100-750 ng/dL

3 pm - 5 pm : <401 ng/dL

11 pm - midnight : <100 ng/dL

Interpretation

Cushing syndrome is characterized by increased salivary cortisol levels, and late-night saliva cortisol measurements may be the optimum test for the diagnosis of Cushing. It is standard practice to confirm elevated results at least once. This can be done by repeat late-night salivary cortisol measurements, midnight blood sampling for cortisol (CORT/8545 Cortisol, Serum), 24-hour urinary free cortisol collection (CORTU/8546 Cortisol, Urine), or overnight dexamethasone suppression testing. Upon confirmation of the diagnosis, the cause of hypercortisolism, adrenal versus pituitary versus ectopic adrenocorticotropic hormone production, needs to be established. This is typically a complex undertaking, requiring dynamic testing of the pituitary adrenal axis and imaging procedures. Referral to specialized centers or in-depth consultation with experts is strongly recommended.

Outreach CPTs

CPT	Modifier (if needed)	Quantity	Description	Comments
82533