Cortisol Total (LC–MS/MS) Biomarker Testing
It measures total cortisol in blood to assess adrenal hormone output and stress physiology, with ordering and results support through Vitals Vault and Quest.
With Vitals Vault, you have access to a comprehensive range of biomarker tests.
Cortisol is one of your body’s main “get-things-done” hormones. It helps regulate energy, blood pressure, blood sugar, immune signaling, and how you respond to physical and emotional stress.
A Cortisol Total LC–MS/MS test measures the total amount of cortisol in your blood at the moment your sample is drawn. Because cortisol follows a strong daily rhythm and is sensitive to medications and illness, the timing and context of the test matter as much as the number.
This page helps you decide whether testing fits your situation and how to interpret low, in-range, and high results in a clinician-guided way.
Do I need a Cortisol Total LC MS test?
You might consider a total cortisol blood test if you and your clinician are trying to explain symptoms that could relate to adrenal hormone output or cortisol regulation. That can include persistent fatigue that does not improve with sleep, unexplained weight change, dizziness or low blood pressure, new easy bruising, muscle weakness, or changes in mood and sleep that feel out of proportion to your circumstances.
Testing is also common when there is a specific clinical question, such as evaluating possible adrenal insufficiency (too little cortisol) or cortisol excess (too much cortisol). It can be part of follow-up if you are using or tapering steroid medications (like prednisone), because external steroids can suppress your body’s own cortisol production.
If you are simply “stressed,” a single cortisol result rarely tells the whole story. Cortisol changes hour-to-hour, and many non-dangerous factors can move it. The test is most useful when it is ordered with the right timing (often morning) and paired with related labs or follow-up testing based on your symptoms.
Your result should support clinician-directed care, not self-diagnosis, because the next steps depend on your history, exam, medications, and the time of day the sample was collected.
This is a laboratory-developed test performed in a CLIA-certified lab using LC–MS/MS; results are for clinical interpretation and are not a standalone diagnosis.
Lab testing
Ready to order Cortisol Total (LC–MS/MS) and schedule a local blood draw?
Schedule online, results typically within about a week
Clear reporting and optional clinician context
HSA/FSA eligible where applicable
Get this test with Vitals Vault
Vitals Vault lets you order Cortisol Total (LC–MS/MS) directly and complete your blood draw through a national lab network. You can use this when you want a clear, documented baseline, when you are rechecking a prior abnormal result, or when you are building a broader lab map with your clinician.
After results post, PocketMD can help you put the number into context, including how collection time, sleep, recent illness, and medications can shift cortisol. If your result suggests you need follow-up, PocketMD can also help you understand which companion tests are commonly used next and what retest timing is reasonable.
If you are tracking changes over time, ordering through the same network can make trending easier, because pre-analytic steps and reporting style are more consistent from test to test.
- Order online and schedule a local blood draw
- PocketMD guidance for next-step questions and retest planning
- Results you can share directly with your clinician
Key benefits of Cortisol Total LC MS testing
- Gives a precise measurement of total cortisol using LC–MS/MS methodology.
- Helps evaluate symptoms that may relate to low cortisol (adrenal insufficiency) when timed appropriately.
- Supports workup of possible cortisol excess when combined with the right confirmatory tests.
- Provides a baseline before and after changes in steroid medications or other therapies that affect cortisol.
- Adds context to fatigue, sleep disruption, blood pressure issues, and blood sugar swings when interpreted with your history.
- Helps guide which follow-up labs may be needed (for example ACTH, DHEA-S, or late-night salivary cortisol).
- Makes it easier to trend results over time when you repeat testing through the same lab network and review patterns in PocketMD.
What is Cortisol Total (LC–MS/MS)?
Cortisol is a steroid hormone made by your adrenal glands. Your brain regulates cortisol through the hypothalamic–pituitary–adrenal (HPA) axis, which increases cortisol in the early morning to help you wake up and generally lowers it at night to support sleep.
“Total cortisol” means the test measures both the cortisol that is bound to proteins in your blood (mainly cortisol-binding globulin, or CBG) and the smaller portion that is unbound (“free”). Only free cortisol is biologically active, but total cortisol is often used as a practical first step because it is widely available and can be interpreted in context.
LC–MS/MS (liquid chromatography–tandem mass spectrometry) is an analytical method that can improve specificity compared with some immunoassays, which may be more vulnerable to cross-reactivity with certain steroid compounds. Even with high-quality measurement, interpretation still depends heavily on collection time and clinical context.
Why timing matters
Cortisol follows a circadian rhythm. A “normal” morning value could be abnormal if it was drawn late in the day, and a “low” afternoon value may be completely expected. When you compare results, make sure you are comparing similar draw times.
Total vs free cortisol
Total cortisol can look higher or lower when CBG changes, even if free cortisol is unchanged. Pregnancy, estrogen-containing birth control, and some liver conditions can raise CBG and increase total cortisol. Low protein states can lower CBG and reduce total cortisol.
What do my Cortisol Total LC MS results mean?
Low cortisol levels
A low total cortisol result can suggest that your body is not producing enough cortisol, especially if the sample was drawn in the early morning when cortisol is usually highest. This pattern may be seen with adrenal insufficiency, suppression from recent or chronic steroid use (pills, injections, inhalers, creams in some cases), or pituitary problems that reduce ACTH signaling. Because cortisol varies by time of day and by lab method, clinicians often confirm low results with repeat morning testing and/or dynamic testing (such as an ACTH stimulation test) rather than relying on one value.
In-range (expected) cortisol levels
An in-range result generally means your total cortisol at that draw time fits the lab’s expected range. It does not always rule out a cortisol-related problem, because some conditions require time-specific testing (for example late-night testing for cortisol excess) or stimulation/suppression tests to uncover abnormal regulation. If you still have significant symptoms, your clinician may look at related markers, medication effects, sleep patterns, and whether the sample timing matched the clinical question.
High cortisol levels
A high total cortisol result can happen for many reasons, including acute stress, pain, poor sleep, intense exercise, illness, depression, or alcohol use. It can also reflect higher CBG from estrogen exposure (pregnancy or estrogen-containing contraceptives), which raises total cortisol even when free cortisol is not truly elevated. Persistent or clearly elevated results—especially if paired with suggestive symptoms—may prompt confirmatory testing that is better suited to diagnosing cortisol excess, such as late-night salivary cortisol, a 24-hour urine free cortisol, or a dexamethasone suppression test.
Factors that influence cortisol
Collection time is the biggest driver, followed by sleep quality and recent stressors. Medications matter: any form of glucocorticoid (like prednisone, hydrocortisone, dexamethasone) can suppress or interfere with interpretation, and estrogen can raise total cortisol by increasing binding proteins. Recent illness, inflammation, major exercise, and shifts in work schedule (night shift, jet lag) can also change your rhythm. If your result seems “off,” it is worth confirming the draw time, reviewing meds and supplements with your clinician, and considering a repeat test under more standardized conditions.
What’s included
- Cortisol, Total, Lc/Ms
Frequently Asked Questions
Do I need to fast for a Cortisol Total (LC–MS/MS) blood test?
Fasting is not always required for cortisol itself, but your clinician may prefer a morning draw and may combine cortisol with other tests that do require fasting. If you are ordering cortisol alone, follow the collection instructions provided with your order and try to keep your routine consistent (sleep, caffeine, exercise) before repeat tests.
What time of day should cortisol be tested?
It depends on the clinical question. Morning (often around 7–10 a.m.) is commonly used to evaluate possible low cortisol because that is when levels are typically highest. If cortisol excess is the concern, late-night testing (often saliva) or suppression testing is usually more informative than a single morning blood value.
Is LC–MS/MS cortisol better than an immunoassay cortisol test?
LC–MS/MS is generally considered more analytically specific and can reduce cross-reactivity seen with some immunoassays. That said, the “best” test still depends on timing, the question being asked, and which confirmatory tests your clinician uses for diagnosis.
Can birth control or pregnancy affect total cortisol results?
Yes. Estrogen can increase cortisol-binding globulin (CBG), which can raise total cortisol even if free cortisol is unchanged. If you are pregnant or using estrogen-containing contraception, tell your clinician so they can interpret total cortisol appropriately or choose a different testing approach.
Can steroid medications change my cortisol level?
Yes. Glucocorticoid medications (oral, injected, inhaled, nasal, topical, or eye preparations) can suppress your body’s cortisol production and can complicate interpretation. Do not stop prescribed steroids on your own; instead, review all steroid exposures with your clinician before testing.
What tests are commonly ordered with cortisol?
Common companion tests include ACTH (to help distinguish adrenal from pituitary causes), DHEA-S, electrolytes (especially sodium and potassium), and sometimes renin/aldosterone depending on symptoms. For suspected cortisol excess, clinicians often use late-night salivary cortisol, 24-hour urine free cortisol, and/or a dexamethasone suppression test rather than relying on a single serum cortisol.
When should I retest cortisol?
Retesting depends on why you tested in the first place. If the result was unexpected or the draw timing was not ideal, repeating under standardized conditions (same time of day, similar sleep and routine) is often helpful. If you are monitoring treatment or steroid tapering, your clinician will usually set the timing based on medication changes and symptoms.