Laboratory: Clinical Biochemistry  (AUTOMATED)
Test Name:
SALIVARY CORTISOL - (Sa)
Test Code: SACO
Clinical Information:
This test is performed at:  Health Sciences Centre
Description: Serum free cortisol diffuses freely into saliva, and so salivary cortisol concentrations reflect serum free cortisol more accurately than serum total cortisol. Salivary cortisol concentrations are independent of the rate of saliva production or flow.
Test Indications: Several night-time (midnight) salivary cortisol measurements can be used as a screening test for Cushing syndrome in patients presenting with signs and symptoms of the disease.
 
Morning salivary cortisol concentrations are decreased in adrenal insufficiency; however this test should be interpreted in conjunction with morning serum total cortisol.
Patient preparation instructions: See patient instructions PB110-80-134 Patient Instructions for Collecting Saliva with the Salivette Kit. 
The patient should avoid eating, drinking, and brushing their teeth for 1 hour prior to collection.
 
Collection Devices:
SARSTEDT Salivette® with synthetic swab
Specimen Required:
Saliva: 0.5 mL
Pediatric Saliva: 0.5 mL

See patient instructions PB110-80-134 Patient Instructions for Collecting Saliva with the Salivette Kit. 
Although each kit contains two (2) collection devices, provide the patient with as many Salivettes as requested by the physician on the requisition.
 
Salivette® kits are available at the following locations in Winnipeg:
- St. Boniface Hospital Biochemistry Laboratory
- Health Sciences Centre Biochemistry Laboratory
- Dynacare at the Winnipeg Clinic, Main Floor, 425 St Mary Ave. Ph: 204-947-5610
Special Processing: IMPORTANT: Record the appearance of the specimen in the REQC comment for each specimen (i.e. colour, turbidity) after centrifugation
Specimen Stability:
Ambient: 1 week
Refrigerated: 1 week
Frozen: 3 months (freeze only once)
Specimens not collected using the Salivette® device, or obviously contaminated with blood, food, or mucus will be rejected.

Adult volume: 0.5 mL (fully saturated swab)
Pediatric volume: 0.5 mL (fully saturated swab)
Shipping & Storage: Store & ship entire Salivette® device(s) refrigerated or ambient. Do not freeze
Testing Laboratory (MB): Health Sciences Centre
Other comments: Do not centrifuge or aliquot the specimen prior to shipping.
Referral:
Requisition:
Reference Values:
A.M. Cortisol (0700 - 0800h):     7.0 - 28 nmol/L
P.M. Cortisol (2300 - 2400h):      3.5 - 7.0 nmol/L
Method of Analysis: Competititve Electrochemiluminescent Immunoassay (ECLIA)
Availability:
Daily
Performed at Health Sciences Centre.
See Also:
More Information:
Additional Information: Give each Salivette® a separate specimen ID number.
Interpretation & Assay Interferences: Competitive immunoassays may cross-react with other steroids when present in high concentrations. For example, patients with congenital adrenal hyperplasia (CAH), adrenal carcinoma, or those treated with metyrapone may generate artefactually elevated salivary cortisol results.
 
Other possible sources of interference:
1) Blood in the saliva can cause falsely-elevated results.
2) Touching the swab with fingers can contaminate the specimen and cause variable results.
3) Use of hydrocortisone cream on the hands, or recent administration of prednisolone or methylprednisolone can lead to specimen contamination and falsely elevated results.
4) Anything that interferes with specimen appearance and quality (e.g. eating, brushing teeth right before collection) may cause spurious results.
References: 1. Elecsys Cortisol II Package Insert. Roche Diagnostics. Version 22.0, English. February 2022.
2. Nieman LK, Biller BMK, Findling JW, et al. The Diagnosis of Cushing’s Syndrome: An Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab. 2008: 93(5): 1526-1540.