Erectile Dysfunction
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.
CBC—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 impotence.
Urinalysis—Urine is analyzed for protein (albumin),
sugar (glucose), and hormone (testosterone) levels that may
indicate diabetes mellitus, kidney dysfunction, and
testosterone deficiency.
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—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.
Prostate examination—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 gauge.
Snap gauge 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
circumference.
Penile biothesiometry—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 impotence.
Vasoactive injection—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).
The Austin Diagnostic Clinic, A
Multi-Specialty Medical Clinic
12221 MoPac Expressway North |
Austin, TX 78758 | 512.901.1111
Serving the communities of Austin, Round Rock, Pflugerville, San
Marcos and
Central Texas since 1952
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