Adrenocorticotropic Hormone (ACTH): Nursing Guide
Plasma ACTH helps clinicians map the hypothalamic-pituitary-adrenal (HPA) axis — especially after hypercortisolism is confirmed and when adrenal insufficiency is suspected. Nurses protect result integrity with early-morning timing, iced EDTA collection, prompt centrifugation and freezing per protocol, and by never interpreting ACTH without paired cortisol and the clinical picture.
Contents
Quick Facts
Key Takeaway
ACTH tells you how hard the pituitary is driving the adrenals — but only when the sample is collected at the right time, handled on ice, and read beside cortisol and symptoms.
Specimen & Collection Details
Nurse quick-reference for collection prep that affects result quality.
Lavender top (EDTA)
K2- or K3-EDTA — pre-chilled per institutional protocol
Plasma (EDTA); morning draw with strict cold-chain handling
Approximately 1 mL plasma after separation — follow the reporting laboratory’s minimum volume requirement
Morning specimen preferred (commonly 7:00–10:00 a.m.) when ACTH follows a diurnal pattern; draw at the exact time ordered for serial or dynamic protocols
May require fasting for several hours — follow the ordering clinician’s and laboratory’s instructions
Collect into pre-chilled EDTA tube, transport on ice, centrifuge at refrigerated temperature within institutional time limits, separate plasma, and freeze immediately per laboratory protocol
Commonly 1–2 days; varies by laboratory
Endocrine / specialty chemistry or send-out reference laboratory
What is Adrenocorticotropic Hormone (ACTH)?
Adrenocorticotropic Hormone (ACTH) is a blood test that measures adrenocorticotropic hormone (ACTH, also called corticotropin) in plasma. ACTH is released by the anterior pituitary and stimulates the adrenal cortex to produce cortisol. Measuring ACTH helps clinicians determine whether cortisol abnormalities originate from the pituitary/adrenal axis (ACTH-dependent) or from independent adrenal overproduction or suppression (ACTH-independent), when interpreted with cortisol and the clinical context.
Overview
Nurses encounter plasma ACTH during endocrine workups for suspected Cushing syndrome, ectopic ACTH production, primary adrenal insufficiency, and hypothalamic-pituitary disorders. Per Endocrine Society guidance, random plasma ACTH is not recommended for initial Cushing syndrome screening — but once hypercortisolism is biochemically confirmed, ACTH helps separate ACTH-dependent from ACTH-independent causes and guides specialist imaging and further testing.
Unlike many routine chemistry tests, ACTH is unstable at room temperature. Official laboratory references require chilled collection, prompt refrigerated centrifugation, and frozen plasma storage. A sample left on the phlebotomy tray can degrade and mislead endocrine decisions. Nurses also coordinate timing with cortisol draws, dexamethasone suppression protocols when ordered, and cosyntropin stimulation testing — which uses synthetic ACTH to assess adrenal reserve but measures the cortisol response rather than baseline plasma ACTH.
Before drawing ACTH, confirm morning timing when ordered, medication and biotin hold instructions, and that pre-chilled EDTA tubes and ice transport are ready. Label with date and time of collection, deliver to the laboratory on ice without delay, and escalate hemodynamic instability or suspected adrenal crisis according to facility policy — do not wait silently for pending ACTH results.
Pre-analytic Specimen Instability (ACTH)
ACTH is not a routine “draw and send” hormone test. Heat-labile specimen degradation, wrong timing, and missing cortisol context can push endocrine teams toward the wrong axis diagnosis. Adrenal crisis can kill before ACTH returns — clinical escalation always precedes passive waiting for results.
- Suspected adrenal crisis with hypotension, hypoglycemia, or severe weakness — treat as emergency per facility policy
- ACTH specimen left at room temperature or rejected for cold-chain failure when results will guide steroid decisions
- Afternoon collection when morning diurnal timing was ordered without prescriber approval
- Interpreting random ACTH alone to screen for Cushing syndrome — not supported by Endocrine Society initial testing guidance
Document: collection time, fasting and medication holds, tube type, ice transport, paired cortisol timing, specimen rejections, crisis escalation, and prescriber notifications.
What Plasma ACTH Can and Cannot Tell You
This test can help identify:
- Whether hypercortisolism appears ACTH-dependent or ACTH-independent when paired with cortisol after confirmed screening abnormalities
- Elevated ACTH with low cortisol pattern suggesting primary adrenal insufficiency in the appropriate clinical context
- Need for specialist dynamic testing, imaging, and endocrine referral
- Pre-analytic quality problems when handling deviates from iced EDTA protocol
This test cannot:
- Screen for Cushing syndrome alone on a random draw — Endocrine Society recommends other initial tests
- Localize pituitary versus ectopic ACTH source without further dynamic and imaging studies
- Diagnose adrenal crisis by itself — cortisol and clinical status drive emergency treatment
- Replace cosyntropin stimulation testing when adrenal reserve assessment is the ordered question
Pre-draw Checks for Plasma ACTH
Verify
Clarify before proceeding when:
- Order lacks timing guidance but laboratory requires morning draw
- No ice transport or pre-chilled tubes available
- Patient took biotin or steroids without documented hold instructions
- Prior ACTH specimen was rejected — confirm recollection protocol before repeat
- Patient is hypotensive, hypoglycemic, or severely symptomatic during draw planning
- Random ACTH ordered as sole Cushing screen without prior hypercortisolism testing
- Specimen label time does not match actual draw time
Reading ACTH With Cortisol and Axis Patterns
Integrate ACTH with simultaneous or recent cortisol, collection time, steroid exposure, symptoms (pigmentation, weight change, muscle weakness, hypertension), and basic metabolic panel trends. One value is rarely decisive.
| Pattern (general) | May suggest | Nursing focus |
|---|---|---|
| High ACTH + high cortisol | ACTH-dependent hypercortisolism workup | Endocrine referral; monitor BP, glucose, potassium, mood, infection risk |
| Low ACTH + high cortisol | ACTH-independent adrenal source pattern | Support adrenal imaging pathway per prescriber; monitor hypercortisolism complications |
| High ACTH + low cortisol | Primary adrenal insufficiency pattern | Adrenal crisis precautions; steroid teaching and emergency plan per team |
| Low ACTH + low cortisol | Secondary/tertiary axis suppression pattern | Medication history critical; gradual steroid taper plans need specialist oversight |
Iced EDTA and Crisis Recognition at the Bedside
| Bedside point | Nursing note |
|---|---|
| Ice immediately | Do not batch ACTH tubes with routine room-temperature chemistry samples |
| Morning matters | An 08:00 order drawn at noon is a different test context — clarify before sending |
| ACTH vs CST | Cosyntropin stimulation injects synthetic ACTH and measures cortisol response — different workflow |
| Cushing screen trap | NCLEX favorite: initial Cushing screening uses cortisol-based tests, not random ACTH alone |
| Biotin hold | Hair/nail vitamins may interfere — 12-hour hold per Mayo protocol when applicable |
| Crisis first | Treat suspected adrenal crisis per protocol — ACTH result can wait clinically |
ACTH Testing in Endocrine Workflow
Diagnostic safety badge: Critical-result test — prompt review and escalation may be required when ACTH guides steroid decisions or when adrenal crisis is suspected.
Check-before-test protocol
- Identity + correct test (plasma ACTH vs stimulation protocol)
- Morning time window + fasting status confirmed
- Pre-chilled EDTA + ice transport ready
- Steroid/biotin history documented
- Crisis assessment and paired cortisol coordination
Critical teach-back questions
- “Can you tell me why this blood test needs to be drawn in the morning and kept on ice?”
- “What weakness, dizziness, or abdominal symptoms should you report right away?”
- “Which medicines or vitamins did you take in the last 24 hours?”
Care coordination: endocrinology, laboratory/phlebotomy, pathology transport, pharmacy for stress-dose steroids, and rapid response per institutional protocol.
Plasma ACTH Quick Clinical Checklist
- Is this plasma ACTH level or a cosyntropin stimulation protocol?
- Was the draw timed correctly and placed on ice immediately?
- What cortisol result pairs with this ACTH sample?
- Did steroids, stress, or biotin affect pre-test conditions?
- Does the patient need crisis escalation now regardless of pending labs?
Why Adrenocorticotropic Hormone (ACTH) is Ordered
ACTH is ordered when clinicians need pituitary-adrenal axis data beyond cortisol alone — typically after initial hypercortisolism testing or when adrenal insufficiency is suspected.
| Clinical Indication | What the Test Answers | Nursing Rationale |
|---|---|---|
| Confirmed or suspected Cushing syndrome — cause differentiation | Is hypercortisolism ACTH-dependent (pituitary/ectopic) or ACTH-independent (adrenal)? | After biochemical confirmation of hypercortisolism, ACTH pattern with cortisol helps direct endocrine imaging and specialist referral per Endocrine Society and Endotext guidance. |
| Suspected primary adrenal insufficiency (Addison disease) | Is the adrenal gland failing with compensatory high ACTH? | Primary adrenal insufficiency typically shows low cortisol with elevated ACTH; nurses support urgent evaluation when crisis is suspected while cosyntropin stimulation may follow per endocrine protocol. |
| Suspected ectopic ACTH syndrome | Is ACTH inappropriately elevated from a non-pituitary source? | Markedly elevated ACTH with Cushing features may prompt search for ectopic sources such as certain lung or neuroendocrine tumors — interpretation requires specialist oversight. |
| Hypothalamic-pituitary axis evaluation with paired cortisol | Does the pituitary signal match adrenal cortisol output? | ACTH with cortisol trends supports secondary adrenal insufficiency workup and post-glucocorticoid withdrawal assessment when ordered by endocrinology. |
Contraindications and Precautions
There is no absolute contraindication to venipuncture for ACTH, but nurses must not proceed when specimen handling cannot meet cold-chain requirements or when timing orders are incompatible with the clinical protocol.
- Sample not collected on ice or delayed centrifugation/freezing — may falsely lower ACTH and suggest incorrect axis interpretation.
- Afternoon or unspecified timing when morning diurnal peak was required — repeat per prescriber and laboratory guidance before major endocrine decisions.
- Using random ACTH alone to screen for Cushing syndrome — not supported by Endocrine Society initial testing recommendations; clarify whether screening cortisol tests were completed.
- Exogenous glucocorticoids suppress ACTH — medication history must be reviewed before interpretation.
- High-dose biotin supplements may interfere with some ACTH immunoassays — the reporting laboratory recommends avoiding biotin-containing supplements for 12 hours before collection.
- Stress, critical illness, and pregnancy alter HPA axis testing — interpret with endocrine specialist input when results conflict with the clinical picture.
- Suspected adrenal crisis (hypotension, refractory hypoglycemia, severe weakness, hyperkalemia, hyperpigmentation progression) — escalate immediately per facility policy while labs are pending.
- Invalid or rejected ACTH specimen when results are needed for steroid management decisions.
- Markedly abnormal ACTH with rapid clinical deterioration, severe hypertension, hypokalemia, or new neuropsychiatric changes suggesting severe hypercortisolism.
Patient Preparation
Preparation focuses on timing, fasting when ordered, medication review, and coordinating special specimen handling with the laboratory before the draw.
Pre-test checksReview oral, inhaled, topical, and injected glucocorticoids; estrogen therapy; drugs affecting cortisol metabolism; and biotin-containing multivitamins or hair/skin/nail supplements. Do not stop prescribed medicines unless the ordering clinician instructs — document what the patient actually took.
Performance — nursing procedure guide
This page is a Tests & Diagnostics guide for Adrenocorticotropic Hormone (ACTH). It emphasizes why the test is ordered, how to interpret results, when to escalate, and preparation factors that affect validity — not step-by-step performance technique (those live under Nursing Procedures when available).
Step-by-step technique, supplies, infection prevention, and immediate post-procedure monitoring for this test are covered in:
Use the Patient preparation, Results and interpretation, and Nursing responsibilities sections on this page for order verification, pre-analytic checks, result follow-up, critical-value escalation, and documentation.
Result follow-up at a glance
Nursing workflow on this page — from order to safe action on results:
Results and Interpretation
Plasma ACTH is reported in pg/mL (or pmol/L depending on the laboratory). Interpretation requires the reporting laboratory’s reference interval, collection time, paired cortisol, and whether the patient has exogenous steroids or acute illness.
Reference ranges, critical values, and protocols may vary by laboratory, institution, patient population, and testing method. Always follow local policy and the reporting laboratory’s reference range.
| Result | Range / Finding | Clinical Meaning | Nursing Action |
|---|---|---|---|
| Within reference interval | Within reporting laboratory morning reference interval — assay-specific; not one universal range | ACTH and cortisol pattern consistent with expected axis feedback for the clinical context | Continue planned endocrine workup; avoid over-reassurance without correlated cortisol and symptoms |
| Borderline / near reference limit | Near cut-off or discordant with cortisol | May require repeat sampling, dynamic testing, or specialist interpretation | Ensure specimen quality and timing were correct; notify prescriber for endocrine follow-up |
| High / above reference interval | Above laboratory reference (often with elevated cortisol) | Suggests ACTH-dependent hypercortisolism (pituitary or ectopic source) when cortisol is high — specialist differentiation required | Communicate to prescriber/endocrine team; monitor BP, glucose, potassium, mood, and infection risk |
| Low / below reference interval | Below laboratory reference (often with low cortisol in primary insufficiency) | May support primary adrenal insufficiency when cortisol is low; suppressed ACTH with high cortisol suggests ACTH-independent Cushing pattern | Assess for adrenal crisis signs; ensure steroid plan is clarified; escalate instability per protocol |
Urgent Clinical Findings and Escalation
Universal numeric critical-value thresholds for plasma ACTH are Turnaround and screening rules vary by institution; follow local institutional policy. Urgent nursing action depends on clinical status, paired cortisol, and local laboratory critical-result policy.
| Critical Finding | Threshold / Value | Immediate Action |
|---|---|---|
| Suspected adrenal crisis with hemodynamic instability | Clinical crisis signs — cortisol may be low regardless of pending ACTH result | Escalate according to facility policy; support prescribed stress-dose steroids and monitoring — do not delay for laboratory confirmation alone |
| Specimen handling failure on axis-critical draw | Warm sample, wrong tube, or missed morning timing when protocol requires recollection | Notify laboratory and prescriber immediately; arrange repeat collection per protocol before major treatment decisions |
| Severe hypercortisolism complications | Marked hypertension, hypokalemia, glucose elevation, psychosis, or infection with very high cortisol pattern | Urgent prescriber/endocrine notification; monitor vitals, glucose, electrolytes, and mental status |
Stop routine workflow and escalate according to facility policy when the patient shows adrenal crisis features, when a compromised ACTH specimen would guide steroid decisions, or when ACTH/cortisol results strongly conflict with rapid clinical deterioration.
Factors Affecting Results
ACTH immunoassays are sensitive to pre-analytic handling and interfering substances. Nurses prevent false reassurance or false alarm by protecting specimen integrity.
- Apparent ACTH elevation from stress, hospitalization, or acute illness unrelated to chronic Cushing disease
- Cross-reactivity or assay interference from biotin or heterophile antibodies in some platforms
- Mislabeled or mixed specimens when multiple timed endocrine draws occur on the same shift
- Falsely low ACTH from room-temperature storage, delayed centrifugation, or improper tube
- Afternoon collection when morning peak was required — may underestimate ACTH secretion
- Recent exogenous glucocorticoids suppressing ACTH while cortisol pattern still being interpreted
- Time of day and diurnal rhythm (morning peak)
- Cold-chain breaks — heat-labile peptide degradation
- Glucocorticoids, biotin supplements, estrogen, and acute stress
Random plasma ACTH is not recommended for initial Cushing syndrome screening per Endocrine Society guidance. ACTH alone does not localize pituitary versus ectopic disease — dynamic tests and imaging follow. Results must always be interpreted with simultaneous or recent cortisol and medication history.
Nursing Responsibilities
Nursing responsibilities center on protocol verification, morning and paired-test timing, cold-chain specimen protection, crisis recognition, and clear communication of handling issues.
Before the TestDocumentation
Documentation should prove specimen integrity and support endocrine interpretation.
“Plasma ACTH drawn 08:12 into pre-chilled lavender EDTA; specimen placed on ice immediately and hand-delivered to lab at 08:19. Patient NPO since midnight per order. Paired AM cortisol drawn 08:10. Biotin supplement held ×12 h per laboratory instruction. No vasovagal symptoms. Prescriber notified that prior afternoon sample was rejected — this is recollection.”
- Exact date and time of collection (critical for diurnal interpretation)
- Fasting status, medication holds, and recent steroid exposure
- Tube type, ice transport, and any handling deviation reported to lab
- Paired tests drawn (cortisol, dexamethasone protocol phase if applicable)
- Patient symptoms, vitals, and crisis escalation if performed
- Result notification and prescriber communication read-back if required
Patient and Family Education
Use plain language while keeping endocrine follow-up expectations clear.
Adrenocorticotropic Hormone (ACTH) NCLEX practice questions
Practice NCLEX-style clinical judgment focused on Adrenocorticotropic Hormone (ACTH) safety and nursing judgment. Use the case tabs (orders, results, assessment, nursing notes), then answer eight Next Gen–style items (including an ordered workflow step) and evaluate outcomes with the answer key.
Select a tab to view orders, results, assessment, and nursing note details for this case.
- Order: Plasma ACTH, AM draw — paired with cortisol
- Indication: Progressive fatigue, hyperpigmentation, weight loss; suspected primary adrenal insufficiency
- Timing: Ordered for 08:00 a.m.; patient arrived fasting at 10:45 a.m.
- Related orders: Morning serum cortisol; basic metabolic panel; cosyntropin stimulation test pending endocrine review
- Result: Prior ACTH specimen rejected — not processed on ice within laboratory time limit
- Trend / prior value: Morning cortisol from prior admission 6.8 µg/dL (reporting lab low for morning); ACTH recollection pending
- Pending tests: Endocrinology consult; cosyntropin stimulation if specimen valid
- Vital signs: HR 108/min, BP 88/54 mmHg, temp 37.1°C, glucose 58 mg/dL (capillary)
- Symptoms: Weakness, dizziness, anorexia, increased skin pigmentation on palmar creases
- Focused assessment: Dry mucous membranes; orthostatic hypotension noted; patient reports missing hydrocortisone for 2 days
- Preparation notes: Phlebotomist placed EDTA tube in room-temperature rack for 25 minutes before ice — reason prior rejection
- Collection events: Recollection supplies ready; patient now hypotensive during standing assessment
- Teaching gaps / safety concerns: Late timing plus prior cold-chain failure; missed steroid doses; hypoglycemia and orthostatic BP drop
Answer key & rationale
Frequently Asked Questions
FAQ
Why must ACTH be collected in the morning?
ACTH follows a diurnal pattern with higher levels in the early morning. standard clinical references and major laboratory references recommend morning draws (often 7:00–10:00 a.m.) so results can be compared with laboratory morning reference intervals.
Does the patient need to fast before a plasma ACTH test?
your health care provider will tell you how to prepare, and you may need to fast for several hours before the test. Follow the specific order and laboratory instructions.
Why is the ACTH blood sample placed on ice?
ACTH is heat-labile and degrades quickly at room temperature. the reporting laboratory and comparable references require pre-chilled EDTA collection, transport on ice, refrigerated centrifugation, and frozen plasma to prevent falsely low results.
Can ACTH alone diagnose Cushing syndrome?
No. The Endocrine Society recommends initial screening with tests such as urine free cortisol, late-night salivary cortisol, or dexamethasone suppression — not random plasma ACTH. After hypercortisolism is confirmed, ACTH helps distinguish ACTH-dependent from ACTH-independent causes.
What is the difference between plasma ACTH and a cosyntropin stimulation test?
Plasma ACTH measures the pituitary hormone level in blood. A cosyntropin stimulation test injects synthetic ACTH (cosyntropin) and measures the adrenal cortisol response at 30 and 60 minutes — primarily to assess adrenal insufficiency per standard clinical references.
Can biotin supplements affect ACTH results?
the reporting laboratory instructs patients to avoid biotin-containing multivitamins and supplements for at least 12 hours before collection because high biotin doses may interfere with some immunoassays. Document supplement use and follow local laboratory guidance.
When should nurses escalate despite pending ACTH results?
Escalate according to facility policy when adrenal crisis is suspected (hypotension, hypoglycemia, severe weakness), when specimen handling failed on a critical draw, or when the patient deteriorates — do not wait silently for ACTH results alone.
References
References
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MedlinePlus. Adrenocorticotropic Hormone (ACTH) Test. U.S. National Library of Medicine.https://medlineplus.gov/lab-tests/adrenocorticotropic-hormone-acth/
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Mayo Clinic Laboratories. ACTH — Adrenocorticotropic Hormone, Plasma. Test Catalog.https://www.mayocliniclabs.com/test-catalog/overview/800208
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Nieman LK; et al. The Diagnosis of Cushing’s Syndrome: An Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab. 2008.https://pubmed.ncbi.nlm.nih.gov/18334580/
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Bancos I; et al. Cushing Syndrome — Endotext. NCBI Bookshelf.https://www.ncbi.nlm.nih.gov/books/NBK279088/
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MedlinePlus Medical Encyclopedia. ACTH stimulation test. U.S. National Library of Medicine.https://medlineplus.gov/ency/article/003696.htm
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Fischli S; et al. Endocrine Testing Protocols: Hypothalamic Pituitary Adrenal Axis. Endotext. NCBI Bookshelf.https://www.ncbi.nlm.nih.gov/books/NBK278940/
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Thiagarajan R; et al. Adrenocorticotropic Hormone (Cosyntropin) Stimulation Test. StatPearls. NCBI Bookshelf.https://www.ncbi.nlm.nih.gov/books/NBK555940/
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University of Iowa Hospitals & Clinics. Adrenocorticotropic Hormone — Pathology Handbook.https://www.healthcare.uiowa.edu/path_handbook/handbook/test2308.html
Editorial Standards & Medical Review
About the author: Sid A. Abdala Balal, RN, writes evidence-based nursing education focused on diagnostic safety, clinical interpretation, and bedside nursing judgment.
Medical review: This guide is reviewed by Dr. Adam Sayedi, MD, for clinical accuracy, diagnostic safety, and alignment with current standards for Adrenocorticotropic Hormone (ACTH).
Policies: Medical Review Process · Editorial Policy · Correction Policy