| Laboratory: | Clinical Biochemistry (AUTOMATED) |
| Test Name: |
SALIVARY CORTISOL - (Sa)
Test Code:
SACO
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| Clinical Information: |
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. Patient preparation instructions: See PB110-85-107 Patient Instructions for Saliva Collection |
| Collection Devices: |
Preferred Device:
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| Specimen Required: |
Saliva: 0.5 mL
Pediatric Saliva: 0.5 mL
Collection Information: Salivette® collection devices are available at (1) St. Boniface Hospital Biochemistry Laboratory and (2) Health Sciences Centre Biochemistry Laboratory. Patients should be provided with as many Salivette® devices as requested on the requisition and copy of collection instructions. Special Processing: (1) Each Salivette® device must be registered with an individual specimen ID (2) Record specimen appearance post centrifugation (e.g. colour, turbidity) under REQC. Rejection Criteria: (1) Collections not using Salivette® devices (2) Contamination with blood, food or mucus 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): Health Sciences Centre Biochemistry Laboratory |
| 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
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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. |