Laboratory: | Clinical Biochemistry (AUTOMATED) |
Test Name: |
SALIVARY CORTISOL - (Sa)
Test Code:
SACO
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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: |
Preferred Device:
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Specimen Required: |
Saliva: 0.5 mL
Pediatric Saliva: 0.5 mL
Collection Information: Salivette® kits are available at: St. Boniface Hospital Biochemistry Laboratory and Health Sciences Centre Biochemistry Laboratory Each kit contains two collection devices, the patient should be provided with as many Salivette® devices/kits as requested by the physician on the requisition. Patient must be provided a copy of patient instructions with Salivette® kit PB110-80-134 Patient Instructions for Collecting Saliva with the Salivette Kit. Special Processing: Appearance of the specimen (colour, turbidity) after centrifugation must be recorded under REQC. Specimens not collected using the Salivette® device, or obviously contaminated with blood, food, or mucus to be rejected. Each Salivette® device must be registered with an individual specimen ID Specimen Stability: Ambient: 72 hours; Refrigerated: 1 week; Frozen: 12 months, freeze only once (centrifuged saliva samples)
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Referral: |
Shipping & Storage: Store & ship entire Salivette® device(s) refrigerated or ambient. Do not freeze.
Testing Laboratory (MB): MS5 – Health Sciences Centre |
Requisition: | |
Reference Values: |
P.M. Cortisol (2300 - 2400h): 3.5 - 7.0 nmol/L
Late night salivary cortisol levels: <7.6 nmol/L (95th percentile) <11.3 nmol/L (97.5th percentile) Method of analysis: Competitive ECLIA Roche immunoassay |
Availability: |
Daily
Performed at Health Sciences Centre.
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See Also: | |
More Information: |
Interpretation & Assay Interferences:
Normal diurnal variation of cortisol may be affected during acute stress, depression, alcoholism, and as a results of numerous drugs (e.g. anticonvulsants, glucocorticoids). Falsely elevated salivary cortisol may be due to blood contamination (bleeding gums due to vigorous brushing or flossing or disease) or from hand contamination (hydrocortisone cream) or due to recent administration of prednisolone. Spurious results may be observed in poor quality samples (traces of food, drinks) or cross-contamination by touching swab with fingers. |