Quick highlights
- Timed PM measurement to assess diurnal cortisol decline
- Useful when evaluating cortisol rhythm abnormalities under clinician care
- Requires precise timing for valid interpretation
- Stress, illness, and sleep patterns can affect results
- Steroid medicines can alter cortisol—disclose all forms
- Usually no fasting required
- Often interpreted with AM cortisol and/or additional endocrine tests
- Home blood collection possible with timed slot planning
- Emphasizes clinician interpretation and test limitations
- SEO coverage: PM cortisol test, evening cortisol blood test, cortisol rhythm test
What’s included
Preparation
- Book collection at the instructed evening time window
- No fasting unless combined tests require fasting
- Avoid unusual stress/exertion before sampling where possible
- Disclose all steroid use and recent illness
- Note sleep schedule/shift work status
- Collect serum blood sample via trained phlebotomist
- Download report from <a href='/my-account/'>View reports</a>
- Review with clinician; further rhythm tests may be advised
FAQs
To assess cortisol later in the day when levels are normally lower, helping evaluate diurnal rhythm patterns.
Usually no.
At the time window specified by your clinician/lab; timing is crucial.
Yes. Stress and illness can elevate cortisol; clinicians interpret with context.
Yes. Steroid medicines can alter cortisol levels; disclose all steroid use.
No. Diagnosis typically requires specialized tests and clinician evaluation.
Late-night salivary cortisol and dexamethasone suppression test, among others.
Yes; inform your clinician about sleep schedule changes.
Often same day or within 24 hours.
Serum blood sample.
Yes, if a timed evening slot is available in your area.
Do not stop without clinician instructions.
Download from <a href='/my-account/'>View reports</a>.
Discuss with your clinician; further endocrine evaluation may be needed.
Notes
Evening cortisol must be compared with morning levels.
