- A medical examination may indicate neurological, vascular, or
hormonal disease, or Peyronie's disease. History of illness,
smoking, drug use, and hypertension can be ascertained with a
thorough examination of health history. Laboratory tests are
performed to identify the underlying cause.
Blood Tests and Urinalysis
- Blood tests can indicate conditions
that may interfere with normal erectile function. These tests
measure hormone levels, cholesterol, blood sugar, liver and
kidney function, and thyroid function. Excess prolactin (hyperprolactinemea)
can lower testosterone levels, which can diminish libido. Both
of these levels are measured, as well as levels of other sex
hormones. If they are persistently low, an endocrinologist
(hormone specialist) should be consulted.
- Complete blood count (CBC) of red cells and white cells is
used to evaluate the presence of anemia. A low level of red
cells limits the body's utilization of oxygen and can lead to
fatigue and general malaise. The level of blood lipids (fats)
such as cholesterol and triglycerides may indicate
arteriosclerosis, which can reduce blood flow to the penis.
Liver and kidney function tests
- Liver and kidney disease can
create horomonal imbalances. Blood tests for liver function
involves analysis of enzyme and serum creatinine levels, which
are indicators of kidney efficiency.
Thyroid function tests
- Thyroid hormones regulate metabolism and
the production of sex hormones; a deficiency may contribute to
- Urine is analyzed for protein (albumin), sugar
(glucose), and hormone (testosterone) levels that may indicate
diabetes mellitus, kidney dysfunction, and testosterone
Erectile Function Tests
- Tests that assess erectile function
examine the blood vessels, nerves, muscles, and other tissues of
the penis and pelvic region.
- Duplex ultrasound is used to evaluate blood
flow, venous leak, signs of artherosclerosis, and scarring or
calcification of erectile tissue. Erection is induced by
injecting prostaglandin, a hormone-like stimulator produced in
the body. Ultrasound is then used to see vascular dilation and
measure penile blood pressure (which may also be measured with a
special cuff). Measurements are compared to those taken when the
penis is flaccid.
- An enlarged prostate, which can be detected
with a digital rectal examination (DRE), can interfere with
blood flow and nerve impulses in the penis.
Penile nerve function
- Tests such as the bulbocavernosus reflex
test are used to determine if there is sufficient nerve
sensation in the penis. The physician squeezes the glans (head)
of the penis, which immediately causes the anus to contract if
nerve function is normal. A physician measures the latency
between squeeze and contraction by observing the anal sphincter
or by feeling it with a gloved finger inserted past the anus.
Specific nerve tests are used in patients with suspected nerve
damage as a result of diabetes or nerve disease.
Nocturnal penile tumescence (NPT)
- It is normal for a man to have
five to six erections during sleep, especially during rapid eye
movement (REM). These erections occur about every 90 minutes and
last for about 30 minutes. Their absence may indicate a problem
with nerve function or blood supply in the penis. There are two
methods for measuring changes in penile rigidity and
circumference during nocturnal erection: snap gauge and strain
- Involves wrapping three plastic bands of varying
strength around the penis. Erectile function is assessed
according to which bands break. Strain gauge involves placing
special elastic bands at the base and tip of the penis. These
bands stretch during erection and register changes in
- This test uses electromagnetic vibration
to evaluate sensitivity and nerve function in the glands and
shaft of the penis. A decreased perception of vibration may
indicate nerve damage in the pelvic area, which can lead to
- When injected into the penis, certain
solutions cause erection by dilating blood vessels in erectile
tissue. Normally, these injections produce an erection lasting
about 20 minutes. During this procedure, penile pressure is
measured and x-rays may be taken of the penile blood vessels
using a special dye (contrast agent).
Erectile Dysfunction Causes
Erectile Dysfunction Diagnosis