Quick Facts
- Sample: 4-point saliva samples (timed throughout the day) plus one blood spot via fingerstick
- Fasting: Not required; maintain normal meal patterns
- Turn-around: 5-7 business days from lab receipt.May take longer based on weather, holiday, or lab delays.
Benefits
- Assess stress hormone patterns and adrenal function without lab visits or appointments
- Identify thyroid dysfunction and autoimmune thyroiditis risk via blood spot testing
- Measure free (bioavailable) cortisol using gold-standard LC-MS/MS methodology
- Capture complete diurnal cortisol rhythm to detect burnout, fatigue, and HPA axis dysregulation
- Receive results with reference ranges within one week
- Continue all prescribed medications during testing; reference ranges adjusted accordingly
- Transparent upfront pricing with no hidden fees or surprise billing
Who Is This Test For?
- Individuals experiencing unexplained chronic fatigue, burnout, or persistent exhaustion
- People with depression, anxiety, or stress-related symptoms seeking physiological assessment
- Women managing irregular cycles, fertility challenges, or PCOS screening
- Anyone baseline testing before stress-management or wellness interventions
- Patients with suspected hypothyroidism, cold intolerance, or weight gain despite diet efforts
- Those monitoring recovery from trauma, PTSD, or high-stress life events
- Privacy-conscious individuals or those in remote areas with limited endocrinologist access
How It Works - Just 3 Steps
- Order and receive your kit at home: Your kit includes four saliva collection tubes, one blood spot card, prepaid return mailer, and detailed collection instructions. No appointment necessary.
- Collect samples at home over one day: Collect saliva at four timed intervals (upon waking, 30 minutes post-waking, midday, and evening), then perform a single fingerstick for blood spot. Follow pre-collection guidelines (no food or drink 30 minutes before saliva samples).
- Mail samples and access results online: Return your samples in the prepaid mailer. Results arrive within 5-7 business days via secure online portal with commentary comparing your results to age-adjusted reference ranges.
FAQ
What is the purpose of this test? The SB-650 measures stress hormone patterns via 4-point salivary cortisol and seven additional adrenal hormones, plus thyroid function (TSH, free T3, free T4, and autoimmune antibodies) via blood spot. Combined assessment is clinically valuable because chronic stress suppresses thyroid hormone conversion and impairs TSH reliability (NIH, 2023).
Who would benefit from this test? Individuals with unexplained chronic fatigue, depression, anxiety, burnout, irregular sleep, hormonal dysregulation, fertility challenges, or autoimmune concerns. Approximately 3.3 million U.S. adults have chronic fatigue syndrome, yet many remain undiagnosed (CDC, 2024). This test enables early screening before symptoms become disabling.
Can I take medications while testing? Yes. Continue all prescribed medications (antidepressants, thyroid replacement, etc.) unless your provider advises otherwise. Inform ZRT if taking oral corticosteroids, HRT, or thyroid medication so reference ranges reflect your supplementation status.
How do I interpret the results? ZRT provides personalized reference ranges adjusted for age, sex, menstrual status, and hormone use. Normal cortisol shows a 50-150% surge 30-45 minutes after waking, with progressive decline through the day. Blunted awakening response suggests burnout; elevated morning cortisol with flattened slope suggests chronic stress. TSH above 2.5 mIU/L or free T4 below 0.8 ng/dL may indicate hypothyroidism; elevated TPO antibodies confirm autoimmune thyroiditis. Discuss results with your healthcare provider for context-specific recommendations.
Is this test accurate? Yes. LC-MS/MS provides 97-98% sensitivity and specificity, superior to immunoassays because it avoids cross-reactivity with structurally related steroids. Saliva LC-MS/MS achieves 95% sensitivity and 91% specificity for detecting Cushing syndrome (JCEM, 2025). ZRT maintains hospital-grade CLIA and CAP certification.
When should I order this test? Order if experiencing persistent fatigue despite adequate sleep, emotional exhaustion unresponsive to stress management, depression or anxiety with suspected physiological roots, or thyroid symptoms (cold intolerance, weight gain, brain fog). Avoid testing during acute illness, extreme stress, menstruation, or within 2 weeks of surgery. Optimal timing is a typical, non-stressed day following your normal routine.
More Details
What is the purpose of this test?
The SB-650 combines saliva and blood spot collection to assess two interconnected hormone systems. Salivary cortisol measured via LC-MS/MS captures free (bioavailable) cortisol at four time points throughout the day, revealing the complete diurnal rhythm. Blood spot testing measures thyroid-stimulating hormone, free T3, free T4, and thyroid peroxidase antibodies. This dual approach identifies HPA axis dysregulation and thyroid dysfunction that conventional screening might miss, while eliminating barriers of physician referrals, office visits, and lab appointments.
What biomarkers are measured in this test?
Saliva biomarkers:
- Cortisol (4-point diurnal collection) - assess stress hormone pattern, cortisol awakening response, and HPA axis function
- Cortisone - evaluate cortisol metabolism and clearance
- DHEA-S (dehydroepiandrosterone-sulfate) - measure adrenal reserve and stress resilience
- Testosterone - assess gonadal and adrenal androgen production
- Estradiol - evaluate ovarian or aromatization-derived estrogen production
- Estrone - secondary estrogen reflecting peripheral estrogen metabolism
- Estriol - estrogen metabolite relevant to reproductive health assessment
- Progesterone - measure luteal phase adequacy and cycle phase
- DHT (dihydrotestosterone) - assess androgen metabolism relevant to hair loss and PCOS
- Allopregnanolone - GABA-active neurosteroid impacting anxiety and mood
- 17-OH Progesterone - assess adrenal enzyme function and screen for adrenal hyperplasia
- Pregnenolone Sulfate - neurosteroid with cognitive and mood impacts
- Androstenedione - androgen precursor reflecting adrenal and gonadal function
- Aldosterone - evaluate mineralocorticoid function and blood pressure regulation
- 7-Keto DHEA - thermogenic metabolite with distinct metabolic roles
- 11-Deoxycortisol - assess adrenal synthesis pathway and enzyme function
- Melatonin - circadian rhythm marker for sleep-wake cycle assessment
Blood spot biomarkers:
- TSH (thyroid-stimulating hormone) - primary thyroid screening and pituitary-thyroid axis assessment
- Free T4 - active thyroid hormone differentiating subclinical from overt hypothyroidism
- Free T3 - most metabolically active thyroid hormone assessing T4-to-T3 conversion
- TPOAb (thyroid peroxidase antibody) - screen for autoimmune thyroiditis and disease progression risk
Who would benefit from this test?
Individuals with unexplained chronic fatigue, burnout, depression, anxiety, irregular sleep, or stress-related symptoms. Women experiencing irregular menstrual cycles, amenorrhea, fertility challenges, or PCOS symptoms benefit from combined cortisol and sex hormone assessment. Those with suspected hypothyroidism (cold intolerance, weight gain, brain fog) or family history of autoimmune thyroid disease should consider combined testing. Patients implementing stress-management interventions, therapy, or wellness protocols benefit from baseline and follow-up assessment. Health-conscious individuals and those in remote areas with limited specialist access value at-home convenience and confidentiality.
When should I order this test?
Order when experiencing persistent fatigue despite adequate sleep, emotional exhaustion unresponsive to stress management, or depression and anxiety with suspected physiological roots. Consider testing if experiencing thyroid symptoms (cold intolerance, weight gain, brain fog, dry skin) or before beginning stress-management programs. For premenopausal women, ideal collection timing is days 19-21 of a regular cycle to capture luteal-phase hormone levels. Avoid testing during acute infection, extreme stress, menstruation, or within 2 weeks of surgery or trauma, which artificially elevate cortisol. Aim for a typical day following your normal routine.
How do I interpret the results?
ZRT provides a report with personalized reference ranges adjusted for:
- Age
- Sex
- Menstrual status
- Hormone supplementation
Normal cortisol pattern
- 50–150% surge in the first 30–45 minutes after waking
- Progressive decline throughout the day (steep diurnal slope)
Abnormal cortisol patterns
- Blunted cortisol awakening response → suggests burnout or chronic fatigue
- Elevated morning cortisol with a flattened daily slope → indicates HPA-axis hyperactivation from chronic stress
- Low afternoon and evening cortisol → suggests adrenal fatigue
Thyroid markers
- Normal TSH range: 0.4–2.5 mIU/L
- TSH > 2.5 mIU/L → suggests hypothyroidism and warrants reflex free T4 testing
- Free T4 < 0.8 ng/dL → indicates overt hypothyroidism
- Low-normal free T3 with high-normal TSH → suggests impaired T4-to-T3 conversion
Autoimmune thyroid disease
- TPO antibodies > 35 IU/mL confirm autoimmune thyroiditis
- Elevated TPO antibodies predict progression to overt thyroid disease
Early detection of abnormal cortisol patterns and thyroid autoimmunity enables timely intervention before symptoms become disabling or disease progression requires lifelong treatment.
Disclaimer: Reference ranges may vary by laboratory. Listed ranges are general guidelines and may differ from those used by the performing lab. Always consult your healthcare provider for interpretation.
Pre-test preparation
Timing:For premenopausal women, collect on days 19-21 of regular cycle (or 5 days before expected menses if cycles are irregular) for luteal-phase assessment. Postmenopausal women, men, and non-cycling individuals may test any day.
Stress and illness: Avoid testing during acute infection, extreme emotional stress, or within 2 weeks of surgery or trauma. Test on a typical day following your normal routine.
Medications and supplements: Continue all prescribed medications (antidepressants, thyroid replacement, antihistamines) unless your provider advises otherwise. Inform ZRT if taking oral corticosteroids, as these suppress cortisol; topical steroids may contaminate samples.
Sleep and substances: Aim for 7-9 hours sleep the night before testing. Avoid alcohol for 24 hours and high-dose caffeine (over 100 mg) on the morning of collection.
Saliva collection requirements: Do not eat, drink (except plain water), smoke, chew gum, or brush teeth for 30 minutes before each saliva sample. If necessary to brush in the morning, do so immediately after the first sample, then wait 30 minutes before the second collection. Rinse mouth with plain water if needed, but wait 5 minutes before collecting.
Blood spot collection: Perform one fingerstick using the provided sterile lancet. Express 3-4 drops of whole blood onto the marked circles on the filter paper card. Allow to air-dry completely (at least 4 hours) at room temperature before placing in the return envelope.
How often should I get tested?
- For stress-management monitoring: Retest every 3-6 months if implementing stress-reduction interventions, therapy, or adrenal-support protocols to assess cortisol normalization and diurnal slope improvement.
- For thyroid management: If TSH is abnormal but free T4 is normal (subclinical hypothyroidism), retest annually or when symptoms change. If starting thyroid replacement therapy, retest 6-8 weeks after dose adjustment, then annually thereafter.
- For baseline assessment: Initial test establishes hormone profile; follow-up timing depends on findings and intervention type.
Why early detection matters
Approximately 3.3 million U.S. adults have chronic fatigue syndrome, yet the majority remain undiagnosed until disease progression becomes debilitating (CDC, 2024). Early HPA axis screening identifies dysregulation before it manifests as treatment-resistant depression or anxiety. Seventy-nine percent of hypothyroid patients test positive for thyroid peroxidase antibodies, confirming autoimmune etiology; early TPOAb detection enables intervention before overt hypothyroidism develops. The direct-to-consumer model saves $100-$300 per test compared to traditional pathways (office visits, travel, lost work time), enabling proactive health management before multisystem disease develops.
Related tests you may consider
NeuroAdrenal Profile, Saliva and Urine - Doctor's Data Kit - Measures cortisol and neurotransmitter levels in the body to detect a hormone imbalance and screen for an adrenal gland disorder.
Hormone Check Blood Test Panel - Measures important hormones like estrogen, progesterone, testosterone, and thyroid levels to help understand how they affect energy, mood, and reproductive health.
Cortisol:Cortisone Ratio Profile Blood Test, LC/MS-MS - Checks the balance between two stress-related hormones to help find out if your body is handling stress properly or if your adrenal glands may not be working right.
