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Testosterone is a steroid hormone (androgen) made by the
testes in males. Its production is stimulated and controlled
by luteinizing hormone (LH), which is manufactured in the
pituitary gland. In males, testosterone stimulates
development of secondary sex characteristics, including
enlargement of the penis, growth of body hair and muscle,
and a deepening voice. It is present in large amounts in
males during puberty and in adult males to regulate the sex
drive and maintain muscle mass. Testosterone is also
produced by the adrenal glands in both males and females
and, in small amounts, by the ovaries in females. In women,
testosterone is converted to estradiol, the main sex hormone
in females.
In men, the test may
be ordered when infertility is suspected or if the patient
has a decreased sex drive or erectile dysfunction, all of
which can result from low testosterone levels.
In women, testosterone testing may be done if a patient has
irregular or no menstrual periods, is having difficulty
getting pregnant, or appears to have masculine features,
such as facial and body hair, male pattern baldness, and a
low voice. Testosterone levels can rise because of tumors
that develop in either the ovary or adrenal gland or because
of other conditions, such as polycystic ovarian syndrome (PCOS).
There is great
variability in testosterone levels between men and a broad
range in age-related values for testosterone. It is normal
for testosterone levels to decline as men age.
However, in males, a decreased testosterone level may
indicate hypothalamic or pituitary disease or damage to the
testes. Genetic diseases also can cause decreased
testosterone production in young men (Klinefelter’s,
Kallman’s, and Prader-Willi syndromes) or testicular failure
and infertility (as in myotonic dystrophy, a form of
muscular dystrophy). A decreased testosterone level also can
indicate impaired testosterone production because of
acquired damage to the testes, such as alcoholism, physical
injury, or viral diseases like mumps.
Increased testosterone levels in males can indicate
testicular tumors, adrenal tumors that are producing
testosterone, or use of androgens (also called anabolic
steroids). Increased testosterone in boys is usually the
cause of early puberty.
In women, increased testosterone levels can indicate
polycystic ovarian syndrome (PCOS) or an ovarian or adrenal
gland tumor.
In boys, the test is
ordered, often along with the FSH and LH tests, if puberty
is delayed or slow in developing. Although there are
differences from individual to individual as to when puberty
begins, generally by the age of 10 years, there are hormonal
and physical manifestations of the onset of puberty. A delay
can occur if the testes do not produce enough testosterone
or if the pituitary does not produce enough LH.
The test also can be ordered if a young boy seems to be
undergoing a very early (precocious) puberty with obvious
secondary sex characteristics, such as an enlarged penis,
development of muscle mass, and growth of body hair. Causes
of precocious puberty in boys, due to increased
testosterone, include various tumors and congenital adrenal
hyperplasia.
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TESTOSTERONE
FREE & TOTAL |
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$148.00 |
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$178.00 |
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Testosterone is present in the blood as
"free" testosterone (2-3%) or bound testosterone. The latter
may be bound to either albumin (a serum protein) or to a
specific binding protein called Sex Steroid Binding Globulin
(SSBG) or Sex Hormone Binding Globulin (SHBG.
SHBG is a
protein that is produced by the liver. It binds tightly to
testosterone, dihydrotestosterone (DHT), and estradiol (an
estrogen) and transports them in the blood in a
metabolically inactive form (non bioavailable). The amount
of SHBG in circulation is affected by age and sex, by
decreased or increased testosterone or estrogen production,
and can be affected by certain diseases and conditions such
as liver disease, hyperthyroidism or hypothyroidism, and
obesity.
Changes in SHBG levels can affect the amount of testosterone
that is available to be used by the body’s tissues.
Normally, about 40% to 60% of testosterone is bound to SHBG,
and most of the rest is weakly and reversibly bound to
albumin. Only about 2% is immediately available to the
tissues as free testosterone.
A
total testosterone test does not distinguish between bound
and unbound testosterone; it determines the overall quantity
of testosterone. In many cases, this is sufficient to
evaluate excessive or deficient testosterone production;
but, if a patient’s SHBG level is not normal, then the total
testosterone may not be an accurate representation of the
amount of testosterone that is available to a patient’s
tissues.
The binding
of testosterone to albumin is not very tight and is easily
reversed; so the term Bioavailable Testosterone (BAT) refers
to the sum of free testosterone plus albumin-bound
testosterone. Alternatively, it is the fraction of
circulating testosterone that is not bound to SSBG. It is
suggested that BAT represents the fraction of circulating
testosterone that readily enters cells and better reflects
the bioactivity of testosterone than does the simple
measurement of serum total testosterone. Also, varying
levels of SSBG can result in inaccurate measurements of BAT.
Decreased SSBG levels can be seen in obesity, hypothyroidism,
androgen use, and nephritic syndrome. Increased levels are
seen in cirrhosis,
hyperthyroidism,
and estrogen use. In these situations, measurement of free
testosterone may be more useful. However, technically, free
testosterone is difficult to measure accurately. |
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$148.00 |
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$178.00 |
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ESTRADIOL
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$89.00 |
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Estrogen is a
group of hormones primarily responsible for the development of female
sex organs and secondary sex characteristics. While estrogen is one of
the major female sex hormones, small amounts are found in males. In
women, follicular stimulating hormone (FSH; produced by the pituitary
gland) stimulates cells (follicles) surrounding the eggs in the ovaries,
causing them to produce estrogen. When the estrogen levels reach a
certain level, the pituitary produces a surge of luteinizing hormone (LH),
which eventually causes the release of the egg, beginning the
preparation for fertilization.
There are three main estrogen fractions: estrone (E1), estradiol (E2),
and estriol (E3).
Estrone (E1) is the major estrogen after menopause. It is derived from
metabolites from the adrenal gland and is often made in adipose tissue
(fat).
Estradiol (E2) is produced in women mainly in the ovary. In men, the
testes and adrenal glands are the principal source of estradiol. In
women, normal levels of estradiol provide for proper ovulation,
conception, and pregnancy, in addition to promoting healthy bone
structure and regulating cholesterol levels. Estradiol levels are used to help evaluate ovarian
function. Estradiol helps diagnose the cause of precocious puberty in
girls and gynecomastia in men. Its main use has been in the differential
diagnosis of amenorrhea (for example, to determine whether the cause is
menopause, pregnancy, or a medical problem). In assisted reproductive
technology (ART), serial measurements are used to monitor follicle
development in the ovary in the days prior to in-vitro fertilization.
Estradiol is also sometimes used to monitor menopausal hormone
replacement therapy.
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PROSTATE SCREEN (PSA)
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$58.00 |
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| The PSA test is a blood test that is
used to screen for the presence of prostate cancer.
Because PSA is produced by the body and can be used to detect disease,
it is sometimes called a biological marker or tumor marker. Prostate specific
antigen is a protein found in the fluid portion of blood, called serum.
PSA is specific to the prostate. No other human tissue or body part can
make it. PSA levels can be measured in an individual's serum.
It is normal for men to have low levels of PSA in their blood; however,
prostate cancer or benign (not cancerous) conditions can increase PSA
levels. As men age, both benign prostate conditions and prostate cancer
become more frequent. The most common benign prostate conditions are prostatitis (inflammation of the prostate) and benign prostatic
hyperplasia (BPH = enlargement of the prostate).
There is no evidence that prostatitis or BPH cause cancer, but it is possible for a man to have
one or both of these conditions and to develop prostate cancer as well.
PSA is only
present in men. PSA is present in all normal prostate tissue. The normal
prostate cell holds onto most of the PSA. Very little leaks into the
bloodstream. The small amount that leaks out is what is measured by the
blood test. Prostate cancer cells actually have less PSA in each cell.
However, the cancer cell tends to leak more PSA into the bloodstream.
Knowing this fact, experts developed a range of expected values in
patients with a normal prostate gland. The PSA value should be less than
4.0. This number reflects the belief that most men, roughly 95%, with
normal prostate glands have a PSA value of 4.0 or less. (See below for
age-specific normal values.) Almost any condition that affects the
prostate can make the PSA rise.
The American Cancer Society and the American Urological Association
recommend that men over age 50 have a yearly PSA. They should also have
a rectal examination of the prostate. High-risk groups should begin
screening at age 40 to 45. Men with a family history of the disease and
African Americans fall into this category.
When evaluating PSA results, the doctor
must also take into account the results of the rectal exam, the
patient's age, previous PSA results, and prostatic size. For example,
findings on a rectal exam must be looked into even if the PSA result is
normal. Recent studies have suggested that the 4.0 level may be too high
for younger men and too low for older men. Many researchers now use the
following levels rather than the 4.0 used in the past. However, more
time is needed to assure that these levels are more accurate.
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AGE |
NORMAL RANGE |
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40 to 50 |
0 to 2.5 |
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50 to 60 |
0 to 3.5 |
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60 to 70, |
0 to 4.5 |
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70 to 80 |
0 to 6.5 |
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If the rectal exam is normal
then the following recommendations are suggested: PSA of 4 or less. If
the PSA level has been measured for the first time and is less than 4,
repeat testing is recommended on a yearly basis. (This number may be
dependent on age. See above for normal values). PSA between 4 and 10.
If the PSA level is greater than 4 but less than 10, a diagnostic
ultrasound of the prostate is recommended. If the ultrasound shows no
suspicious areas, the prostate can be monitored through regular testing
and exams.
Another option is to take random biopsies from various parts of the
prostate. If observation alone is used, the PSA should be repeated in 4
to 6 months and no later than a year. If the ultrasound shows a
suspicious area, then biopsy of the area needs to be performed. This can
be done at the time of the ultrasound. The patient will need to take
antibiotics ahead of time.
If the
PSA is greater than 10, diagnostic ultrasound of the prostate with
biopsies is the recommended course. If the ultrasound shows no
suspicious areas, then random biopsies of the prostate are taken. If the
ultrasound shows suspicious areas, then biopsies of the areas along with
random biopsies need to be done. If previous PSA values are available,
test results will be evaluated differently. The PSA level almost always
rises if cancer is growing. Any PSA level that is rising is suspicious.
However, a high PSA level may not mean that cancer is present. For
example, a male with a stable PSA of 8 over a three-year period
is probably at less risk than a male with a PSA of 2, 4, and 6 over the
same time frame. This is because the second patient's rising levels
suggest growth. This makes it suspicious for cancer. If the first
patient had a negative biopsy when the first high PSA value occurred,
there may be no need to repeat the biopsies. If the PSA level jumped to
10 or 15 for no apparent reason, then repeat ultrasound and biopsies
would be called for. Recent studies suggest that either a 20% rise or a
measurable rise of 0.75 in PSA in one year should prompt a closer look.
Ultrasound and biopsy may be needed.
PSA levels alone do not give doctors enough information to distinguish
between benign prostate conditions and cancer but it is the first
screening step for any man over 50. Your physician will take the result
of the PSA test into account when deciding whether to check further for
signs of prostate cancer.
The U.S. Food and Drug Administration (FDA) has approved the PSA test
along with a digital rectal exam DRE to help detect prostate cancer in
men age 50 and older. During a DRE, a doctor inserts a gloved finger
into the rectum and feels the prostate gland through the rectal wall to
check for bumps or abnormal areas. Together, these tests can help
doctors detect prostate cancer in men who have no symptoms of the
disease.
The FDA has also approved the PSA test to monitor patients with a
history of prostate cancer to see if the cancer has come back
(recurred). An elevated PSA level in a patient with a history of
prostate cancer does not always mean the cancer has come back. A man
should discuss an elevated PSA level with his doctor. The doctor may
recommend repeating the PSA test or performing other tests to check for
evidence of recurrence.
It is important to note that a man who is receiving hormone therapy for
prostate cancer may have a low PSA reading during, or immediately after,
treatment. The low level may not be a true measure of PSA activity in
the man’s body. Men receiving hormone therapy should talk with their
doctor, who may advise them to wait a few months after hormone treatment
before having a PSA test.
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For whom might a PSA screening test be recommended?
Doctors’ recommendations for screening vary. Some encourage yearly
screening for men over age 50, and some advise men who are at a higher
risk for prostate cancer to begin screening at age 40 or 45. Others
caution against routine screening, while still others counsel men about
the risks and benefits on an individual basis and encourage men to make
personal decisions about screening.
Several risk factors increase a man’s chances of developing prostate
cancer. These factors may be taken into consideration when a doctor
recommends screening. Age is the most common risk factor, with nearly 70
percent of prostate cancer cases occurring in men age 65 and older.
Other risk factors for prostate cancer include family history, race, and
possibly diet. Men who have a father or brother with prostate cancer
have a greater chance of developing prostate cancer. African American
men have the highest rate of prostate cancer, while Asian and Native
American men have the lowest rates. In addition, there is some evidence
that a diet higher in fat, especially animal fat, may increase the risk
of prostate cancer.
PSA test results report the level of PSA detected in the blood. The test
results are usually reported as nanograms of PSA per milliliter (ng/ml)
of blood. In the past, most doctors considered PSA values below 4.0 ng/ml
as normal. However, recent research found prostate cancer in men with
PSA levels below 4.0 ng/ml. Many doctors are now using the following
ranges, with some variation:
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LEVEL OF PSA IN BLOOD |
RISK OF PROSTATE CANCER |
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0 to 2.5 ng/ml |
low |
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2.6 to 10 ng/ml |
slightly to
moderately elevated |
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10 to 19.9 ng/ml |
moderately
elevated |
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20 ng/ml or
more |
significantly
elevated |
There is no specific normal or abnormal PSA level. However, the higher a
man’s PSA level, the more likely it is that cancer is present. But
because various factors can cause PSA levels to fluctuate, one abnormal
PSA test does not necessarily indicate a need for other diagnostic
tests. When PSA levels continue to rise over time, other tests may be
needed.
There
are many possible reasons for an elevated PSA level, including prostate
cancer, benign prostate enlargement, inflammation, infection, age, and
race.
If no other symptoms suggest cancer, the doctor may recommend repeating
DRE (Digital Rectal Exam) and PSA tests regularly to watch for any changes. If a man’s PSA
levels have been increasing or if a suspicious lump is detected during
the DRE, the doctor may recommend other tests to determine if there is
cancer or another problem in the prostate. A urine test may be used to
detect a urinary tract infection or blood in the urine. The doctor may
recommend imaging tests, such as ultrasound (a test in which
high-frequency sound waves are used to obtain images of the kidneys and
bladder), x-rays, or cystoscopy (a procedure in which a doctor looks
into the urethra and bladder through a thin, lighted tube). Medicine or
surgery may be recommended if the problem is BPH or an infection.
If cancer is suspected, a biopsy is needed to determine if cancer is
present in the prostate. During a biopsy, samples of prostate tissue are
removed, usually with a needle, and viewed under a microscope. The
doctor may use ultrasound to view the prostate during the biopsy, but
ultrasound cannot be used alone to tell if cancer is present.
Detection does not always mean saving lives: Even though the PSA test
can detect small tumors, finding a small tumor does not necessarily
reduce a man’s chance of dying from prostate cancer. PSA testing may
identify very slow-growing tumors that are unlikely to threaten a man’s
life. Also, PSA testing may not help a man with a fast-growing or
aggressive cancer that has already spread to other parts of his body
before being detected.
False positive test results (also called false positives) occur
when the PSA level is elevated but no cancer is actually present. False
positives may lead to additional medical procedures that have potential
risks and significant financial costs and can create anxiety for the
patient and his family. Most men with an elevated PSA test turn out not
to have cancer; only 25 to 30 percent of men who have a biopsy due to
elevated PSA levels actually have prostate cancer.
False negative test results (also called false
negatives) occur when the PSA level is in the normal range even though
prostate cancer is actually present. Most prostate cancers are
slow-growing and may exist for decades before they are large enough to
cause symptoms. Subsequent PSA tests may indicate a problem before the
disease progresses significantly.
Using the PSA test to screen men for prostate cancer is controversial
because it is not yet known if this test actually saves lives. Moreover,
it is not clear if the benefits of PSA screening outweigh the risks of
follow-up diagnostic tests and cancer treatments. For example, the PSA
test may detect small cancers that would never become life threatening.
This situation, called overdiagnosis, puts men at risk for complications
from unnecessary treatment such as surgery or radiation.
The procedure used to diagnose prostate cancer (prostate biopsy) may
cause side effects, including bleeding and infection. Prostate cancer
treatment may cause incontinence (inability to control urine flow) and
erectile dysfunction (erections inadequate for intercourse). For these
reasons, it is important that the benefits and risks of diagnostic
procedures and treatment be taken into account when considering whether
to undertake prostate cancer screening.
The benefits of screening for prostate cancer are still being studied.
The National Cancer Institute (NCI) is currently conducting the
Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial, or PLCO
trial, to determine if certain screening tests reduce the number of
deaths from these cancers. The DRE and PSA are being studied to
determine whether yearly screening to detect prostate cancer will
decrease a man’s chance of dying from prostate cancer. Full results from
this study are expected in several years. Scientists also are
researching ways to distinguish between cancerous and benign conditions,
and between slow-growing cancers and fast-growing, potentially lethal
cancers. Some of the methods being studied are:
PSA velocity:
PSA velocity is based on changes in PSA levels over time.
A sharp rise in the PSA level raises the suspicion of cancer.
Age-adjusted PSA:
Age is an important factor in increasing PSA levels.
For this reason, some doctors use age-adjusted PSA levels to determine
when diagnostic tests are needed. When age-adjusted PSA levels are used,
a different PSA level is defined as normal for each 10-year age group.
Doctors who use this method generally suggest that men younger than age
50 should have a PSA level below 2.4 ng/ml, while a PSA level up to 6.5
ng/ml would be considered normal for men in their 70s. Doctors do not
agree about the accuracy and usefulness of age-adjusted PSA levels.
PSA density:
PSA density considers the relationship of the PSA level to
the size of the prostate. In other words, an elevated PSA might not
arouse suspicion if a man has a very enlarged prostate. The use of PSA
density to interpret PSA results is controversial because cancer might
be overlooked in a man with an enlarged prostate.
Free versus complexed (attached) PSA:
PSA circulates in the blood in two
forms: free or attached to a protein molecule. With benign prostate
conditions, there is more free PSA, while cancer produces more of the
attached form. Researchers are exploring different ways to measure PSA
and to compare these measurements to determine if cancer is present.
Alteration of PSA cutoff level:
Some researchers have suggested lowering
the cutoff levels that determine if a PSA measurement is normal or
elevated. For example, a number of studies have used cutoff levels of
2.5 or 3.0 ng/ml (rather than 4.0 ng/ml). In such studies, PSA
measurements above 2.5 or 3.0 ng/ml are considered elevated. Researchers
hope that using these lower cutoff levels will increase the chance of
detecting prostate cancer; however, this method may also increase
overdiagnosis and false positive test results and lead to unnecessary
medical procedures.
Protein patterns:
Scientists are also studying a test that can rapidly
analyze the patterns of various proteins in the blood. Researchers hope
that this technique can determine if a biopsy is necessary when a person
has a slightly elevated PSA level or an abnormal DRE.
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IGF1 Growth Hormone |
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$158.00 |
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| IGF-1 is measured to help diagnose the cause of
growth abnormalities and to evaluate pituitary
function. It is not diagnostic of GH deficiency but
may be ordered along with
GH stimulation tests to offer additional
information. IGF-1 levels and the measurement of GH
can also provide information related to GH
insensitivity.
IGF-1 may be ordered with other pituitary hormone
tests, such as
adrenocorticotropic hormone (ACTH), to
help diagnose
hypopituitarism. It may be used to
monitor the effectiveness of treatment for growth
hormone deficiencies and growth hormone
insensitivity.
IGF-1 testing and a GH suppression test can be
used to detect a GH-producing pituitary tumor. Its
presence is then confirmed with imaging scans that
help identify and locate the tumor. If surgery is
necessary, GH and IGF-1 levels are measured after
the tumor’s removal to determine whether or not all
of it was successfully removed. Drug and/or
radiation therapy may be used in addition to (or
sometimes instead of) surgery to try to decrease GH
production and return IGF-1 to normal or near normal
concentrations. IGF-1 may be used to monitor the
effectiveness of this therapy at regular intervals
for years afterward to monitor GH production and to
detect tumor recurrence.
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THYROID PROFILE |
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$98.00 |
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Temp Log
The symptoms of a low body temperature are
classic for low thyroid function and they often get better with thyroid
medicine. Body temperatures are normally lower in the morning, higher in the
afternoon, and lower again in the evening. So if the temperatures are low
during the day when they're supposed to be at their highest, that's better
evidence that there's a problem. Temperature patterns are also important and
illuminating. How patients feel can be affected not only by how high or low
their temperatures are but also on how steady their temps are. One temperature reading a day is not
enough to see how widely the temperature is fluctuating, but more than three
a day can be too time consuming.
T3 uptake
This test measures the
amount of triiodothyronine, or T3, in the blood. T3 is one of two
major hormones produced by the thyroid gland (the other hormone is called
thyroxine, or T4). The thyroid gland is a small butterfly-shaped organ that
lies flat across your windpipe. The hormones it produces control the rate at
which the body uses energy. Their production is regulated by a feedback
system. When blood levels of thyroid hormones decline, the hypothalamus (an
organ in the brain) releases thyrotropin releasing hormone, which stimulates
the pituitary (a tiny organ below the brain and behind the sinus cavities)
to produce and release thyroid-stimulating hormone (TSH). TSH then
stimulates the thyroid gland to produce and/or release more thyroid
hormones. Most of the thyroid hormone produced is T4. This hormone is
relatively inactive, but it is converted into the much more active T3 in the
liver and other tissues.
If the thyroid gland
produces excessive amounts of T4 and T3, then the patient may have symptoms
associated with hyperthyroidism, such as nervousness, tremors of the hands,
weight loss, insomnia, and puffiness around dry, irritated eyes. In some
cases, the patient’s eyes cannot move normally and they may appear to be
staring. In other cases, the patient’s eyes may appear to bulge.
If the thyroid gland
produces insufficient amounts of thyroid hormones, then the patient may have
symptoms associated with hypothyroidism and a slowed metabolism, such as
weight gain, dry skin, fatigue, and constipation. Blood levels of hormones
may be increased or decreased because of insufficient or excessive
production by the thyroid gland, due to thyroid dysfunction, or due to
insufficient or excessive TSH production related to pituitary dysfunction.
Fatigue
Headaches & Migraines
PMS
Easy Weight Gain
Depression
Irritability
Fluid Retention
Anxiety & Panic Attacks
Hair Loss
Poor Memory
Poor Concentration
Low Sex Drive
Unhealthy Nails
Dry Skin & Hair
Cold Intolerance
Low Motivation
Low Ambition
Insomnia - Heat Intolerance
Allergies
Acne
Carpal Tunnel Syndrome
Hives.....and many others
About 99.7% of the T3
found in the blood is attached to a protein (primarily thyroxine-binding
globulin ( TBG) but also several other proteins) and the rest is free
(unattached). Separate blood tests can be performed to measure either the
total (both bound and unattached) or free (unattached) T3 hormone in the
blood.
When TBG is increased, T3 uptake is decreased, and
vice versa. T3 Uptake does not measure the level of T3 or T4 in serum.
Increased T3 uptake (decreased TBG) is seen in chronic
liver disease, protein-losing states, and with use of the following drugs:
androgens, barbiturates, bishydroxycourmarin, chlorpropamide,
corticosteroids, danazol, d-thyroxine, penicillin, phenylbutazone, valproic
acid, and androgens. It is also seen in hyperthyroidism.
Decreased T3 uptake
(increased TBG) may occur due to the effects of exogenous estrogens
(including oral contraceptives), pregnancy, acute hepatitis, and in
genetically-determined elevations of TBG. Drugs producing increased TBG
include clofibrate, lithium, methimazole, phenothiazines, and
propylthiouracil. Decreased T3 uptake may occur in hypothyroidism
T4
T4 is one of two major
hormones produced by the thyroid gland (the other is called triiodothyronine,
or T3). The thyroid is a small, butterfly-shaped gland located just below
the Adam's apple. This gland plays a vital role in controlling the rate at
which your body uses energy.
The body has a
feedback system that turns thyroid hormone production on and off. When the
level of T4 in the bloodstream decreases, the hypothalamus (an organ in the
brain) releases thyrotropin releasing hormone, which stimulates the
pituitary gland (an organ below the hypothalamus) to release
thyroid-stimulating hormone (TSH), which in turn stimulates the thyroid
gland to make and/or release more T4. As blood concentrations of T4
increase, the amount of TSH released decreases.
T4 makes up nearly all
of what we call thyroid hormone, while T3 makes up less than 10%. Inside the
thyroid gland, T4 is produced, bound to a protein called thyroglobulin, and
stored. When the body requires thyroid hormone, the thyroid gland produces
some T4 or T3 and/or releases stored T4 into circulation. In the blood, T4
is present in a free (not bound) and protein-bound form (primarily bound to
thyroxine-binding globulin). The concentration of free T4 is only about 0.1%
of that of total T4, but the free T4 is the portion of thyroxine that is
active. T4 only becomes an active thyroid hormone when it is converted into
T3 in the liver or other tissues.
If the thyroid gland
does not produce sufficient T4 (due to thyroid dysfunction or to
insufficient TSH), then the affected patient experiences symptoms of
hypothyroidism such as weight gain, dry skin, cold intolerance, irregular
menstruation, and fatigue. If the thyroid gland produces too much T4, the
rate of the patient’s body functions will increase and cause symptoms
associated with hyperthyroidism such as increased heart rate, anxiety,
weight loss, difficulty sleeping, tremors in the hands, and puffiness around
dry, irritated eyes.
The most common causes
of thyroid dysfunction are autoimmune-related Graves' disease causes
hyperthyroidism and Hashimoto's thyroiditis causes hypothyroidism. Both
hyper- and hypothyroidism can also be caused by thyroiditis (thyroid
inflammation), thyroid cancer, and excessive or deficient production of TSH.
The effect of these conditions on thyroid hormone production can be detected
and monitored by measuring the total T4 (includes bound and free portion) or
the free T4 (only unbound).
This is a measurement of the total thyroxine in the serum, including both
the physiologically active (free) form, and the inactive form bound to
thyroxine-binding globulin (TBG). It is increased in hyperthyroidism and in
euthyroid states characterized by increased TBG (See "T3 uptake," above, and
"FTI," below). Occasionally, hyperthyroidism will not be manifested by
elevation of T4 (free or total), but only by elevation of T3 (triiodothyronine).
Therefore, if thyrotoxicosis is clinically suspect, and T4 and FTI are
normal, the test "T3-RIA" is recommended (this is not the same test as "T3
uptake," which has nothing to do with the amount of T3 in the patient's
serum).
T4 is decreased in hypothyroidism and in euthyroid states
characterized by decreased TBG. A separate test for "T4" is available, but
it is not usually necessary for the diagnosis of functional thyroid
disorders.
T7 (FTI)
This is a convenient parameter with mathematically accounts for the
reciprocal effects of T4 and T3 uptake to give a single figure which
correlates with free T4. Therefore, increased FTI is seen in
hyperthyroidism, and decreased FTI is seen in hypothyroidism. Early cases of
hyperthyroidism may be expressed only by decreased thyroid stimulation
hormone (TSH) with normal FTI.
This test measures the
amount of thyroid-stimulating hormone (TSH) in your blood. TSH is produced
by the pituitary gland, a tiny organ located below the brain and behind the
sinus cavities. It is part of the body’s feedback system to maintain stable
amounts of the thyroid hormones thyroxine (T4) and triiodothyronine (T3) in
the blood. Thyroid hormones help control the rate at which the body uses
energy. When concentrations decrease in the blood, the hypothalamus (an
organ in the brain) releases thyrotropin releasing hormone (TRH). This
stimulates the release of TSH by the pituitary gland, and then TSH in turn
stimulates the production and release of T4 and T3 by the thyroid gland, a
small butterfly-shaped gland that lies flat against the windpipe. When all
three organs are functioning normally, thyroid production turns on and off
to maintain blood thyroid hormone levels.
If there is pituitary
dysfunction, then increased or decreased amounts of TSH may result. If TSH
concentrations are increased, the thyroid will make and release
inappropriate amounts of T4 and T3 and the patient may experience symptoms
associated with hyperthyroidism (overactive thyroid), such as rapid heart
rate, weight loss, nervousness, hand tremors, irritated eyes, and difficulty
sleeping. If there is decreased production of thyroid hormones
(hypothyroidism), then the patient may experience symptoms such as weight
gain, dry skin, constipation, cold intolerance, and fatigue. In addition to
pituitary dysfunction, hyper- or hypothyroidism can occur if there is a
problem with the hypothalamus (insufficient or excessive TRH). They may also
occur with a variety of thyroid diseases that affect thyroid hormone
production regardless of the amount of TSH present in the blood
Early cases of hypothyroidism may be
expressed only by increased TSH with normal T7 FTI. Currently, the method of
choice for screening for both hyper- and hypothyroidism is the serum TSH.
Modern methodologies ("ultra sensitive TSH") allow accurate determination of
the very low concentrations of TSH at the physiological cutoff between the
normal and hyperthyroid states
TSH has been recognized as an exquisitely sensitive indicator of thyroid
status. TSH assays (second or third generation) have therefore been widely
adopted as the front-line thyroid function test. In ambulatory patients with
intact hypothalamic and pituitary function, a normal TSH result excludes
hypo or hyperthyroidism; whereas elevated and suppressed TSH results are
diagnostic of hypo and hyperthyroidism, respectively.
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$98.00 |
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INSULINE LEVEL |
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$148.00 |
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| Insulin levels are most frequently ordered following an abnormal glucose test and/or when a
patient has acute or
chronic symptoms of
hypoglycemia, such as sweating,
palpitations, hunger, confusion, blurred vision, dizziness,
fainting, and seizures (although these can be caused by other
conditions along with low blood glucose).
Insulin and
C-peptide are produced by
the body at the same rate as part of the activation and division of
proinsulin in the pancreas. Both may be ordered to evaluate how much
insulin in the blood is due to endogenous production (what your body
is making) and how much is from exogenous (produced outside the
body) sources. Insulin tests will reflect the total, while C-peptide
will reflect only the endogenous insulin.
Your doctor also may order both tests to verify that an
insulinoma has been successfully removed. If you are one of the few
people who have received an islet cell transplant to restore your
insulin-producing capability, your insulin level may be monitored to
determine whether or not this procedure is successful over time.
If you have documented hypoglycemia, if you have symptoms
suggesting insulin either is being inappropriately released or
utilized by your body, and sometimes if you have
diabetes and your doctor wants
to monitor your insulin production; to document
insulin resistance in patients
with Polycystic Ovarian Syndrome (PCOS),
pre-diabetes or
heart disease (especially if you
are overweight), Metabolic Syndrome,
or disorders related to the pituitary or adrenal glands
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