Why would a practitioner order an extra cortisol timepoint?

When the standard diurnal curve suggests a rhythm disturbance but lacks the temporal detail to localise it, or when symptoms cluster around a time not covered by default intervals, an extra sample can reveal subtle phase shifts, blunted segments, or elevated nadir values.

Can a single cortisol value diagnose adrenal fatigue?

No. A single timepoint has no interpretive value in isolation and must be read within the complete diurnal curve. Adrenal fatigue is not a recognised diagnosis in mainstream endocrinology; confirmed adrenal insufficiency requires formal dynamic testing.

How accurate is the timing of the extra sample?

Timing accuracy is critical. Cortisol follows a steep diurnal slope, so even a fifteen-minute deviation can shift the result substantially. Patients must document the exact collection time for valid interpretation.

Is saliva collection affected by food or toothbrushing?

Yes. Samples should be collected at least thirty minutes after eating, drinking anything other than water, brushing teeth, or smoking to avoid contamination. Blood in saliva from gingival inflammation can spuriously elevate cortisol.

Are salivary cortisol results comparable to serum cortisol?

No. Salivary cortisol measures the free, unbound fraction and is used for diurnal rhythm assessment. Serum measures total cortisol and is the standard for acute endocrine diagnosis. The two are complementary but not interchangeable.

How should the sample be stored and shipped?

Saliva tubes should be frozen until batch shipment to the DUTCH laboratory in the prepaid kit packaging. Exact handling instructions are provided with the kit; follow them to maintain specimen stability.

How long do results take from the DUTCH laboratory?

Typically ten to fourteen business days from receipt of the complete sample set. Because this is an add-on, it is usually analysed with the main panel in a single batch.

Does this test diagnose Cushing syndrome?

No. While multiple elevated late-night salivary cortisol samples can support further investigation for Cushing syndrome, diagnosis requires formal endocrine workup including serum, urine, and dynamic suppression testing under specialist supervision.

BML-ADR-019adrenal stressUSA

Add-On Extra Cortisol Marker

The Add-On Extra Cortisol Marker is a single additional salivary free cortisol timepoint that extends the temporal resolution of a diurnal rhythm assessment. Ordered when a standard four- or five-point curve is inconclusive, it fills a gap in the sampling schedule to localise rhythm disturbances, phase shifts, or symptom-correlated cortisol excursions in functional HPA axis evaluation.

Biomarkers

Saliva

Sample

10–14 business days

Turnaround

Fasting

What is the Extra Cortisol test?

The Add-On Extra Cortisol Marker is a single additional salivary cortisol collection that extends the temporal resolution of a diurnal cortisol assessment. Standard protocols sample cortisol at four or five fixed times across the day to capture the rhythm; an extra timepoint fills a gap — for instance, mid-afternoon or late evening — when the standard curve does not adequately characterise a suspected abnormality. Practitioners order it when initial results hint at a rhythm disturbance but lack the granularity to localise it, or when symptoms cluster around a particular hour that is not covered by the default schedule. Because this is an add-on rather than a standalone test, it is always interpreted within the complete diurnal profile. A single cortisol value in isolation tells the clinician almost nothing; its position relative to waking, mid-morning, and bedtime samples gives it meaning. The extra marker is used to refine, not replace, the broader rhythm assessment.

What does the Extra Cortisol test measure?

Cortisol(Salivary Free Cortisol (Single Timepoint))

Range: Time-dependent; varies by collection interval and proprietary DUTCH reference data.Optimal: Optimal ranges are context-dependent: waking cortisol should be robust, mid-morning values should show a sharp decline, and evening samples should reach a physiological nadir. An extra timepoint is judged by whether it fits the expected trajectory or reveals a dysregulated segment.ng/mL / nmol/L

Salivary cortisol reflects the unbound, biologically active fraction of circulating cortisol and closely tracks rapid fluctuations in hypothalamic-pituitary-adrenal axis output. Because cortisol secretion follows a pronounced diurnal rhythm — highest on waking, falling sharply through the morning, and reaching a nadir at night — each salivary sample captures the axis at that specific moment. An add-on timepoint expands the diurnal curve, improving resolution of blunted or delayed rhythms that a standard four-point collection might miss.

An extra cortisol timepoint increases the sensitivity of diurnal rhythm assessment, particularly when practitioners suspect a subtle phase shift, a mid-afternoon nadir that is too high or too low, or need to document cortisol kinetics around a symptom window. It is ordered as an add-on to a baseline diurnal panel rather than as a standalone test, since a single isolated value has limited interpretive power without the rest of the curve.

Why is the Extra Cortisol test ordered?

Patients undergoing DUTCH comprehensive hormone testing in whom initial four- or five-point cortisol curves suggest a subtle or atypical rhythm that would benefit from a sixth or seventh sample
Evaluation of suspected delayed cortisol awakening response or phase-shifted rhythms in shift workers or individuals with circadian misalignment
Assessment of mid-afternoon cortisol kinetics in patients reporting fatigue, hyperarousal, or glycaemic instability confined to a specific time window not captured by standard intervals
Monitoring of HPA axis dynamics during adrenal support or stress-management interventions, where serial resolution helps document trajectory changes
Investigation of suspected subclinical Cushing syndrome or cyclical hypercortisolism, where additional late-night samples strengthen detection of elevated nadir cortisol
Functional-medicine practitioners seeking detailed cortisol profiling in complex chronic-fatigue or burnout presentations, where rhythm nuance informs therapeutic targeting

Sample collection and turnaround

Sample type

Saliva

Fasting required

Collection method

At-home collection kit

Turnaround

10–14 business days

Collection notes

Saliva is self-collected at home using a DUTCH test kit at the practitioner-specified time, which is chosen to fill a gap in the standard diurnal schedule. Patients expectorate into a collection tube, record the exact collection time, and ship the sample to the DUTCH laboratory. The collection should occur at least thirty minutes after eating, drinking (except water), brushing teeth, or smoking, and ideally during a typical day free from acute illness or extreme stress.

Specimen requirements

Approximately 1–2 mL saliva per timepoint, stored frozen until batch shipment to the DUTCH laboratory. The kit includes pre-labelled tubes, collection instructions, and prepaid return shipping. Maintain chain of custody and accurate time documentation.

What can affect Extra Cortisol results?

variableTime of sample collection

Cortisol follows a steep diurnal slope, so even a fifteen-minute deviation from the prescribed collection time can shift the result substantially; strict adherence to timing and documentation is essential for valid interpretation.

variableSleep deprivation and shift work

Acute sleep loss and circadian disruption alter the amplitude and phase of cortisol secretion, so results reflect the rhythm at the time of collection rather than a stable baseline trait.

variableOral contamination and recent food or drink

Saliva samples should be collected before brushing teeth, eating, or drinking anything other than water to avoid contamination; blood in the saliva from gingival inflammation can spuriously elevate cortisol.

elevatesAcute stress and physical exertion

Immediate psychological or physical stress raises cortisol within minutes, so sample collection during or shortly after a stressful event does not reflect basal rhythm and should be avoided or repeated.

variableExogenous corticosteroids and hormonal therapies

Oral, inhaled, or topical corticosteroids suppress endogenous cortisol; oestrogen and testosterone can modulate cortisol-binding globulin and free cortisol, so a full medication and supplement history is mandatory.

variableAssay method and laboratory differences

DUTCH uses proprietary LC-MS/MS methods and reference data; salivary cortisol values are not directly comparable to serum, urine, or other salivary platforms, so serial monitoring should remain with the same laboratory.

What do Extra Cortisol results mean?

Elevated

An elevated cortisol value at an extra timepoint may indicate sustained HPA axis activation if it occurs in the evening or overnight, raising suspicion for cyclical hypercortisolism or subclinical Cushing syndrome. Mid-day elevations can reflect phase-shifted rhythms or sustained stress responses; clinical correlation and confirmation with standard endocrine workup are necessary when Cushing is suspected.

Normal

A cortisol value that falls on the expected diurnal trajectory for that timepoint supports a preserved rhythm at that hour. However, normal rhythm does not exclude clinically significant stress or fatigue, which are multi-dimensional and not cortisol-dependent alone.

Reduced

A low cortisol value at an extra timepoint — particularly if waking or morning samples are also blunted — may suggest HPA axis hypofunction, though one low point in isolation is not diagnostic. Functional adrenal fatigue is a contested concept; confirmed adrenal insufficiency requires formal dynamic testing (ACTH stimulation) and is a distinct clinical entity.

Note: A single extra timepoint has no interpretive value in isolation and must be read within the complete diurnal curve. Timing accuracy is paramount. Salivary cortisol is a functional marker; abnormal results warrant correlation with clinical presentation and, if Cushing or adrenal insufficiency is suspected, formal endocrine evaluation rather than reliance on saliva testing alone.

Frequently asked questions

It is a single additional salivary cortisol sample collected at a practitioner-specified time to extend the resolution of a diurnal cortisol curve. It is ordered as an add-on to a standard four- or five-point panel, not as a standalone test.

How to access the Extra Cortisol test

The Extra Cortisol reference page is free and open to all practitioners. Create a free practitioner account to see pricing, save tests to your list, and generate requisition forms. Verification takes 1–2 business days.

Create Free Account

About this page

Published: October 7, 2026

Last reviewed: October 7, 2026

References:

Nieman LK, et al. The diagnosis of Cushing's syndrome: an Endocrine Society clinical practice guideline. (2008)
Hellhammer DH, et al. Salivary cortisol as a biomarker in stress research. Psychoneuroendocrinology. (2009)
Elder GJ, et al. The cortisol awakening response — applications and implications for sleep medicine. Sleep Med Rev. (2014)
Cadegiani FA, Kater CE. Adrenal fatigue does not exist: a systematic review. BMC Endocr Disord. (2016)

This content is for licensed healthcare practitioners only and does not constitute medical advice. Clinical decisions should be based on the full clinical picture and not on any single test result.