Bone Density Scan (DEXA): Nursing Guide
Dual-energy X-ray absorptiometry measures bone mineral density to estimate osteoporosis and fracture risk — nurses verify screening indication, preparation that affects scan validity, low-dose radiation safety, and T-score follow-up with fall prevention and treatment coordination.
Contents
Quick Facts
Key Takeaway
The main nursing priority with DEXA is confirming the right patient and indication, preparation that keeps the measurement valid — especially holding calcium supplements and removing metal — then communicating T-score
Imaging Parameters & Safety
Nurse quick-reference for imaging prep, safety screening, and transport.
Dual-energy X-ray absorptiometry (DEXA / DXA)
Not applicable — DEXA does not use iodinated or oral contrast
Uses low-dose ionising radiation; dose is small compared with many CT studies (protocol-dependent)
Scan often a few minutes; total visit longer if registration and positioning are included
Usually supine on a padded table; hip and spine regions imaged per protocol
No fasting usually required; body-composition protocols may require overnight fast per local policy
What is Bone Density Scan (DEXA)?
Bone Density Scan (DEXA) is a noninvasive imaging test that uses two X-ray energy levels to measure bone mineral density (BMD), most often at the lumbar spine and hip. It is the standard technique referenced by the World Health Organization for classifying bone density using T-scores and for estimating fracture risk when combined with clinical factors.
Overview
DEXA is common in primary care, rheumatology, endocrine, and osteoporosis clinics — and on inpatient units when prednisone or other glucocorticoid therapy or fragility fracture prompts bone-health evaluation. Nurses rarely operate the densitometer, but they coordinate screening eligibility, preparation, transport, pregnancy checks, result communication, and referral to treatment or fall-prevention pathways.
Because T-scores guide antiresorptive therapy and fracture-risk counseling, preparation errors or missed symptoms can delay appropriate treatment or leave an acute vertebral fracture unrecognized. A normal or stable DEXA does not replace assessment when the patient reports new height loss, kyphosis, or severe back pain.
Before DEXA, confirm calcium supplements were held for at least 24 hours, remove metal from the scan area, and ask about pregnancy or recent barium/contrast studies that may require rescheduling. After the scan, reinforce fall precautions and ensure results reach the prescriber — escalate new neurologic deficits or severe acute back pain according to facility protocol.
DEXA Validity, Radiation, and Fracture-Risk Safety
DEXA is low risk for most patients, but invalid preparation, missed pregnancy screening, and overlooking acute fracture symptoms can harm outcomes. Low T-scores require action — not automatic reassurance.
- Calcium supplements taken within 24 hours of lumbar spine imaging
- Recent barium or contrast studies that artifact the spine without rescheduling
- Acute severe back pain or neurologic deficits scheduled only for routine outpatient DEXA
- Recurrent falls with injury despite known osteoporosis — fall pathway not activated
Document: calcium-hold compliance, pregnancy screen, sites scanned, T-score communication, fall teaching, and escalation for red-flag symptoms.
What Bone Density Scan (DEXA) Can and Cannot Tell You
This test can help identify:
- Low bone mineral density and international health authorities T-score categories (normal, osteopenia, osteoporosis)
- Baseline BMD before antiresorptive or anabolic therapy and serial monitoring on treatment
- Fracture risk estimation when combined with age, sex, and clinical risk tools (e.g., FRAX where used)
- Progressive BMD loss in patients on long-term glucocorticoids or other bone-toxic medicines
This test cannot:
- Diagnose vertebral fracture morphology alone — imaging or clinical correlation may be needed
- Replace fall-prevention assessment or home safety evaluation
- Rule out future fractures when T-score is normal or improving on therapy
- Determine treatment plan alone — prescriber integrates FRAX, history, labs, and preferences
Pre-scan Checks for Valid DEXA Results
Verify
Clarify before proceeding when:
- Order does not match screening vs monitoring indication
- Patient took calcium or high-calcium antacids within 24 hours
- Barium or spinal contrast within institutional delay window
- Pregnancy cannot be excluded per policy
- Acute severe back or hip pain suggests fracture — may need urgent pathway first
- Patient cannot lie still or supine safely without plan
- Prior DEXA on different scanner/site — clarify comparison method with radiology
Reading T-scores, Z-scores, and Fracture Risk for Nursing Action
Integrate DEXA with fracture history, height loss, falls, glucocorticoid use, and osteoporosis medicines when available. Trends on serial DEXA matter for treatment monitoring.
| Clinical context | Pair with DEXA | Nursing focus |
|---|---|---|
| Postmenopausal screening | T-score −2.6; no prior fracture | Treatment counseling, fall prevention, follow-up interval |
| Long-term prednisone | T-score −1.8 with height loss | Bone-protective therapy review, calcium/vitamin D adherence |
| On bisphosphonate therapy | T-score improved from −2.7 to −2.1 | Reinforce adherence; continue falls surveillance |
| New thoracic pain | Prior normal DEXA | Do not dismiss — escalate for vertebral fracture workup |
Calcium Supplements, Metal, and Fall Risk at the Bedside
| Bedside point | Nursing note |
|---|---|
| Morning calcium | Most common prep error — verify hold at bedside, not only in clinic instructions |
| Multivitamins | Many contain calcium; confirm all sources |
| Metal belts/jeans | Can require repeat hip views — remind before leaving ward |
| Height loss | Measure serial height; >2 cm loss may indicate vertebral fracture |
| Glucocorticoids | Long-term oral steroids accelerate bone loss — flag for bone-health pathway |
| False reassurance | Normal T-score does not eliminate fall fracture risk |
DEXA Screening and Treatment Monitoring Workflow
Diagnostic safety badge: Routine diagnostic test — standard identification, preparation, and result-follow-up checks still apply; escalate when red-flag symptoms suggest fracture or neurologic compromise.
Check-before-test protocol
- Identity + indication + central vs peripheral order
- Calcium-hold and multivitamin review
- Pregnancy screen when required
- Barium/contrast timing
- Metal removal, mobility plan, and fall-risk escort
Critical teach-back questions
- "Can you tell me why this bone density scan is being done?"
- "What should you avoid taking for 24 hours before the test?"
- "Which symptoms should you report even if your last scan was normal?"
Care coordination: primary prescriber, radiology/densitometry, pharmacy, endocrinology/rheumatology, physical therapy, and fall-prevention services when indicated.
Bone Density Scan Quick Clinical Checklist
- Was calcium held for at least 24 hours?
- Is pregnancy status documented when policy requires?
- Any recent barium or contrast that requires delay?
- Does the patient have new back pain, height loss, or falls needing escalation?
- Has T-score been communicated with fall-prevention and treatment follow-up?
Why Bone Density Scan (DEXA) is Ordered
DEXA is ordered when clinicians need to screen for osteoporosis, diagnose low bone mass, monitor response to therapy, or assess fracture risk in patients with risk factors such as postmenopause, long-term glucocorticoids, or prior fragility fracture.
| Clinical Indication | What the Test Answers | Nursing Rationale |
|---|---|---|
| Osteoporosis screening in at-risk adults | Does this patient meet guideline-based screening criteria? | Supports preventive counseling, baseline BMD, and treatment decisions when density is low. |
| Monitoring antiresorptive or anabolic therapy | Is BMD changing as expected on treatment? | Helps track therapy response; nurses reinforce adherence and scheduled follow-up scans. |
| Glucocorticoid or endocrine-related bone loss | Is steroid or hormonal therapy increasing fracture risk? | Guides calcium/vitamin D optimization, fall prevention, and prescriber review of bone-protective therapy. |
| Fragility fracture or height loss evaluation | Is low bone density contributing to fracture risk? | Pairs imaging with history, exam, and labs; acute fracture symptoms may need urgent workup beyond routine DEXA timing. |
Contraindications and Precautions
DEXA is generally avoided or deferred when pregnancy is possible, when recent barium or contrast would artifact the spine, or when the patient cannot lie still or supine safely. Nurses clarify with radiology and the prescriber rather than proceeding with invalid prep.
- New severe back pain, especially after minimal trauma — may indicate vertebral fracture.
- Leg weakness, saddle anesthesia, or bowel/bladder dysfunction — escalate urgently per protocol.
- Suspected hip fracture on exam — orthopedic/urgent pathway may precede outpatient DEXA.
- Calcium tablets within 24 hours can falsely elevate spine density on some scans.
- Metal, dense clothing fasteners, or recent spinal surgery hardware may affect measurement sites.
- Possible pregnancy — confirm status and follow institutional policy before radiation exposure.
- New neurologic deficits or progressive back pain with fever (possible infection or cord compression).
- Clinical hip fracture or inability to weight-bear after a fall — urgent assessment before routine DEXA.
- T-score in osteoporosis range with recurrent falls or high-energy mechanism — fall-prevention and prescriber review.
Patient Preparation
Preparation is minimal for most central DEXA scans but directly affects measurement validity. Follow the radiology order, institutional checklist, and prescribing clinician instructions.
Pre-test checksReview glucocorticoids, anticonvulsants, heparin, aromatase inhibitors, and other medicines associated with bone loss when interpreting indication and follow-up — but do not independently hold prescribed medicines for DEXA unless authorized by policy or the responsible clinician. Document medicine reconciliation and bone-health teaching provided.
Where the test is performed
This page is a Tests & Diagnostics guide for Bone Density Scan (DEXA). 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).
Bone Density Scan (DEXA) is performed in radiology or dedicated bone densitometry services. Nurses focus on screening indication, preparation that affects measurement validity, T-score and fracture-risk communication, and escalation when symptoms suggest acute fracture or neurologic compromise — not scanner operation.
Use the preparation, results, and nursing responsibility sections below for safety checks, interpretation, escalation, and documentation — not equipment operation or departmental imaging protocols.
Result follow-up at a glance
Nursing workflow on this page — from order to safe action on results:
Results and Interpretation
DEXA reports BMD in g/cm² and international health authorities-based T-scores (and often Z-scores). Nurses integrate results with age, sex, fracture history, medicines, falls, and calcium/vitamin D status — not the numeric score alone.
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 |
|---|---|---|---|
| Normal bone density (international health authorities T-score) | T-score −1.0 or above (normal bone density per international health authorities) | Lower fracture risk relative to osteoporosis range but not zero — falls and comorbidities still matter | Reinforce fall prevention, calcium/vitamin D as ordered, and rescreen per guideline |
| Low bone mass / osteopenia range | T-score between −1.0 and −2.5 (osteopenia / low bone mass) | Increased fracture risk; FRAX or clinical factors may guide treatment | Ensure prescriber review, lifestyle teaching, and follow-up plan documented |
| Osteoporosis threshold (T-score) | T-score −2.5 or below (osteoporosis threshold) | High fracture risk; may prompt pharmacologic therapy and fall-prevention referral | Communicate result, reinforce adherence, monitor for new fractures and falls |
| Low Z-score for age (when reported) | Z-score −2.0 or below in premenopausal women or men under 50 (when reported) | May suggest secondary osteoporosis — warrants further evaluation beyond T-score alone | Notify prescriber; support workup for secondary causes per local pathway |
Urgent Clinical Findings and Escalation
DEXA does not use laboratory critical values, but certain clinical findings during or after scheduling require urgent action independent of BMD results.
| Critical Finding | Threshold / Value | Immediate Action |
|---|---|---|
| Suspected acute vertebral or hip fracture | Severe localized pain, inability to bear weight, or new deformity | Stop routine outpatient pathway; escalate for imaging/orthopedic evaluation per protocol |
| Neurologic deficit with back pain | Leg weakness, numbness, bowel/bladder dysfunction | Activate local emergency response per protocol; do not delay for scheduled DEXA |
| Recurrent falls with head injury or anticoagulant use | Fall with injury despite known low BMD | Assess injury, notify prescriber, initiate fall-prevention and fracture pathway |
Stop routine workflow and escalate according to facility policy when the patient develops acute severe back or hip pain, neurologic deficits, inability to mobilize safely, or falls with injury — even if prior DEXA was normal or the scan is not yet complete.
Factors Affecting Results
BMD and T-scores can be affected by patient factors, technique, and timing relative to supplements, prior imaging, and anthropometrics.
- Aortic calcification or osteophytes may falsely increase spine BMD
- Recent calcium ingestion within 24 hours may artifact spine measurement
- Hip arthroplasty or spinal hardware limits standard measurement sites
- Peripheral DEXA (heel/wrist) may not reflect central fracture risk as well as spine/hip
- Single measurement cannot detect all future fractures — clinical risk factors remain important
- Very low body weight or scoliosis may complicate spine interpretation
- Recent barium exam or spinal contrast — often requires 10–14 day delay
- Metal objects, dense clothing, or external orthotics over scan region
- Different scanner or site compared with prior study — compare trends cautiously
DEXA measures BMD, not bone quality or trabecular microarchitecture. It does not diagnose vertebral fracture on its own — vertebral imaging may be needed when morphology is suspected. Peripheral devices may screen but central spine/hip DEXA is preferred for treatment decisions in many guidelines. All results require clinical context.
Nursing Responsibilities
Nursing care centers on valid preparation, safe transport, fracture-risk communication, fall prevention, and timely follow-up on low T-scores.
Before the TestDocumentation
Clear documentation supports fracture-prevention continuity and audit trails.
“Central DEXA lumbar spine and left hip completed at 1030. Calcium supplements held >24 h verified. Pregnancy status N/A (postmenopausal). Metal removed; patient tolerated supine positioning without distress. Result communicated to primary prescriber: T-score −2.7 lumbar spine (osteoporosis range). Fall-prevention teaching provided; patient verbalized understanding to remove throw rugs and use assistive device at night.”
- Indication, order verification, and scan date/time
- Preparation (calcium hold, metal removal, pregnancy screen)
- Sites imaged and patient tolerance
- T-score/Z-score summary and prescriber notification
- Fall-prevention and treatment teaching provided
- Follow-up scan interval or referral plans
Patient and Family Education
Use plain language while emphasizing preparation, what the scan feels like, and what symptoms require immediate reporting.
Bone Density Scan (DEXA) NCLEX practice questions
Practice NCLEX-style clinical judgment focused on Bone Density Scan (DEXA) 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: Central DEXA spine and hip — outpatient bone health clinic
- Indication: Postmenopausal osteoporosis screening; long-term prednisone 10 mg daily × 8 months
- Timing: Scheduled 0900; patient took calcium carbonate with breakfast today
- Related orders: Calcium, vitamin D, BMP; alendronate discussion pending DEXA
- Result: Prior DEXA 2 years ago: T-score −1.6 lumbar spine; today’s scan pending
- Trend / prior value: Reports 2 cm height loss since last visit; occasional ibuprofen for back ache
- Pending tests: Formal T-score report and prescriber treatment plan
- Vital signs: T 36.8 °C, HR 82/min, BP 128/76, RR 16, SpO₂ 98% on room air
- Symptoms: Mild thoracic aching; ambulates with cane; no leg weakness
- Focused assessment: Kyphotic posture; steady gait with cane; last fall 3 weeks ago (no injury)
- Preparation notes: Patient states she “always” takes calcium with breakfast; metal belt not removed at check-in
- Collection events: Sent to scan alone despite unsteady gait; barium swallow 5 days ago not flagged
- Teaching gaps / safety concerns: Calcium within 24 h; recent barium study; fall risk; height loss trend
Answer key & rationale
Frequently Asked Questions
FAQ
Why is DEXA ordered instead of a regular X-ray?
Standard X-rays show fractures and anatomy but cannot quantify bone mineral density as accurately as DEXA. DEXA is the standard technique for measuring BMD and applying international health authorities T-score classifications to estimate fracture risk.
Does the patient need to fast before DEXA?
Routine central DEXA usually does not require fasting — patients may eat normally on the day of the exam per RadiologyInfo.org and standard clinical references. Specialized body-composition protocols may require overnight fasting per local policy.
Why must calcium supplements be held before DEXA?
Official patient guidance recommends not taking calcium supplements for at least 24 hours before DEXA because ingested calcium can artifact lumbar spine measurements and reduce accuracy.
What do T-score and Z-score mean?
T-score compares BMD to a healthy young adult reference (international health authorities categories: −1.0 or above normal; between −1.0 and −2.5 osteopenia; −2.5 or below osteoporosis). Z-score compares to age-matched peers and may prompt secondary osteoporosis workup when markedly low in younger adults.
Can pregnant patients have DEXA?
Patients should tell the team if pregnancy is possible. Although DEXA uses low-dose radiation, pregnancy status should be assessed and scanning deferred or modified per institutional policy when pregnancy is confirmed or cannot be excluded.
Does a normal DEXA rule out fractures?
No. DEXA estimates fracture risk from BMD but does not diagnose all fractures. Vertebral fractures may be present with minimal symptoms, and clinical assessment remains essential.
How often should DEXA be repeated?
Repeat intervals depend on baseline T-score, treatment, and guidelines — often 1–2 years when monitoring therapy, but not specified as a single universal interval in the published references. Follow prescriber and local bone-health policy.
References
References
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Radiological Society of North America. Bone Density Scan (DEXA or DXA). RadiologyInfo.org; reviewed 2024.https://www.radiologyinfo.org/en/info/dexa
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U.S. National Library of Medicine. Bone mineral density test. MedlinePlus.https://medlineplus.gov/ency/article/007197.htm
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U.S. Preventive Services Task Force. Osteoporosis to Prevent Fractures: Screening. JAMA. 2018;319(24):2521–2531.https://www.uspreventiveservicestaskforce.org/uspstf/recommendation/osteoporosis-screening
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National Institute of Arthritis and Musculoskeletal and Skin Diseases. Osteoporosis Overview. NIH.https://www.niams.nih.gov/health-topics/osteoporosis
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National Institute for Health and Care Excellence. Osteoporosis: assessing the risk of fragility fracture. NICE Guideline CG146.https://www.nice.org.uk/guidance/cg146
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International Society for Clinical Densitometry. Official Positions. ISCD.https://iscd.org/learn/official-positions/
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National Health Service. Bone density scan (DEXA scan). NHS.uk.https://www.nhs.uk/conditions/dexa-scan/
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Dual-Energy X-Ray Absorptiometry. In: StatPearls. Treasure Island (FL): StatPearls Publishing; 2024.https://www.ncbi.nlm.nih.gov/books/NBK519042/
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 Bone Density Scan (DEXA).
Policies: Medical Review Process · Editorial Policy · Correction Policy