Medical Tests for Erectile Dysfunction
Understanding the various medical tests used to diagnose erectile dysfunction and identify underlying causes for effective treatment planning.
Why Medical Tests Are Important
Medical tests help doctors identify the underlying causes of erectile dysfunction, which is crucial for developing an effective treatment plan. Since ED can be caused by physical, psychological, or mixed factors, comprehensive testing ensures the right approach.
Key Goal: Determine whether ED is caused by physical problems (vascular, neurological, hormonal), psychological factors, or a combination of both.
Blood Tests
Hormone Tests
Testosterone Levels
- • Total testosterone: Overall hormone level
- • Free testosterone: Active, available hormone
- • Bioavailable testosterone: Usable by body
- • Normal range: 300-1000 ng/dL (total)
- • Best time: Morning (8-10 AM)
Other Hormones
- • LH (Luteinizing Hormone): Stimulates testosterone
- • FSH (Follicle Stimulating Hormone): Sperm production
- • Prolactin: Can suppress testosterone if high
- • TSH (Thyroid): Affects metabolism and libido
- • SHBG: Protein that binds testosterone
Metabolic Tests
Diabetes Screening
- • Fasting glucose
- • HbA1c (3-month average)
- • Glucose tolerance test
- • Insulin levels
Cardiovascular Risk
- • Total cholesterol
- • LDL ("bad") cholesterol
- • HDL ("good") cholesterol
- • Triglycerides
General Health
- • Complete blood count
- • Kidney function
- • Liver function
- • Vitamin D levels
Physical Examination
General Physical Exam
- • Vital signs: Blood pressure, heart rate, weight
- • Cardiovascular: Heart sounds, pulse strength
- • Neurological: Reflexes, sensation testing
- • Endocrine: Signs of hormone imbalance
- • Vascular: Peripheral pulse examination
Genital Examination
- • Penis: Size, shape, any abnormalities
- • Testicles: Size, consistency, masses
- • Prostate: Digital rectal exam (if indicated)
- • Peyronie's disease: Plaque or curvature
- • Sensation: Nerve function testing
Specialized Diagnostic Tests
Vascular Tests
Penile Doppler Ultrasound
Measures blood flow to and from the penis using sound waves.
- • Injection of vasodilator medication
- • Measurement of arterial blood flow
- • Assessment of venous leakage
- • Takes 30-60 minutes
Intracavernosal Injection Test
Direct injection into penis to test erectile response.
- • Uses prostaglandin E1 or similar
- • Evaluates erectile response
- • Tests blood vessel function
- • May cause temporary erection
Neurological Tests
Penile Biothesiometry
Tests nerve sensitivity in the penis using vibration.
- • Measures vibration sensation
- • Detects nerve damage
- • Non-invasive procedure
- • Takes 10-15 minutes
Bulbocavernosus Reflex
Tests nerve pathways involved in erection.
- • Stimulation of glans penis
- • Measures reflex response
- • Evaluates spinal cord function
- • Quick office procedure
Sleep Studies
Nocturnal Penile Tumescence (NPT)
Monitors erections during sleep to distinguish physical from psychological causes.
- • Overnight monitoring device
- • Measures frequency and rigidity
- • Normal: 3-5 erections per night
- • Can be done at home
RigiScan Testing
Advanced monitoring of nocturnal erections with detailed measurements.
- • Measures rigidity and tumescence
- • Multiple nights of monitoring
- • Computer analysis of data
- • Gold standard for NPT testing
Understanding Test Results
Normal Results Suggest
- • Normal NPT: Physical function intact, likely psychological cause
- • Normal blood flow: Vascular system functioning properly
- • Normal hormones: Endocrine system not the cause
- • Normal nerves: Neurological function preserved
Abnormal Results May Indicate
- • Poor blood flow: Vascular ED requiring specific treatment
- • Low testosterone: Hormone replacement may help
- • Nerve damage: Neurogenic ED, often from diabetes
- • Venous leak: Blood doesn't stay trapped in penis
When Are These Tests Needed?
Always Recommended
- • Medical history and physical exam
- • Basic blood tests (testosterone, glucose)
- • Blood pressure measurement
- • Cholesterol screening
Sometimes Needed
- • Doppler ultrasound
- • Nocturnal erection testing
- • Injection testing
- • Specialized hormone tests
Rarely Needed
- • Arteriography (X-ray of arteries)
- • Cavernosometry (pressure testing)
- • MRI of pelvis
- • Nerve conduction studies
After Testing
Once testing is complete, your doctor will review the results and develop a personalized treatment plan based on the underlying causes identified. Most men can be successfully treated regardless of the test results.