Salivary Cortisol

General Information

The level of cortisol in saliva normally drops to low levels overnight. However, people with Cushing's syndrome show high levels late in the evening and overnight, and may be asked to collect a sample of saliva at midnight. Normally, this test is done at home and delivered to hospital in the next few days.

Patient Preparation

Individuals should avoid eating and brushing teeth for 30 minutes before collecting saliva samples to minimise the potential for blood contamination.

Saliva specimens should be collected using a Sarstedt cortisol salivette. Saliva collected into a plain container by passive drool is also acceptable.

Notes

Salivettes for saliva collection can be ordered from the laboratory on the Queen Elizabeth Hospital site.

Reference Range

Early morning range (7-9 a.m.): 3.2-22.8 nmol/L

Late night range (11 p.m. to 12 a.m.): <3.2 nmol/L

Source of Reference Range

Provided by Reference Laboratory

Specifications

EQA Scheme?: Yes
EQA Status: Satisfactory

Department

Specimen Transport

Sample Preparation

Turnaround Time

Sample Stability