Hussam elmouzi clinical pathologist al borg laboratory 2. We wish to acknowledge the generous permission given by drs. Some clinicians also measure serum total t 3 level thyroid function testing in critically ill patients usually shows low serum. Uk guidelines for the use of thyroid function tests.
Interpretation of laboratory thyroid function tests. Interpretation of thyroid function tests sciencedirect. Ppt d interpreting thyroid function tests powerpoint. Loading slideshow in 5 seconds interpreting thyroid function tests powerpoint presentation. If thyroid function assessment is indicated for critically ill patients, serum tsh and free t 4 concentrations should be measured. Interpretation of thyroid function tests the lancet. Editor oreilly is correct in highlighting the difficulties in interpreting the results of thyroid function tests but overstates his view that the clinical aspects of thyroid disease have been downgraded. Thyroid function tests tft are often abnormal in patients with nonthyroidal illness nti. Ppt thyroid disease powerpoint presentation free to. Interpretation of laboratory thyroid function tests 1. The results of thyroid function tests tfts must always be interpreted in light of the clinical status of the. There are several different thyroid function tests. However, there remain a few situations in which the results of tsh, free t4, and free t3 assays tend to point in different directions, as well as cases in whom thyroid.
A collection of guides to interpreting various laboratory tests, including liver function tests lfts, thyroid function tests tfts and more. A free powerpoint ppt presentation displayed as a flash slide show on id. No one single laboratory test is 100% accurate in diagnosing all types of thyroid disease. The history and physical examination, along with thyroid function tests, enable the clinician to make the diagnosis of thyrotoxicosis. Ppt interpreting thyroid function tests powerpoint. Thyroid tests assess inherent thyroid gland function radioactive iodine uptake test is used to assess intrinsic function of the thyroid gland this test is not specific and the reference range should be adjusted based on local population this test is indirect measure of thyroid activity 21. There are no abnormalities on clinical examination. This test is used to evaluate thyroid function and sometimes used to diagnose fertility problems.
T3 should be added if there is a suggestion of thyrotoxicosis, as it alone may be elevated in some cases of hyperthyroidism. Thyroid diseases are among the most prevalent of medical conditions. Interpretation of laboratory thyroid function tests slideshare. Changes in tsh can serve as an early warning system often occurring before the actual level of thyroid hormones in the body becomes too high or too low. Thyroid function tests leeds teaching hospitals nhs trust. Tsh thyroidstimulating hormone tsh is excreted by the pituitary gland and acts to stimulate the production of t4 by the thyroid. Thyroid hormones and thyroid function tests duration. Multiple tests over 3 to 6 mo should be performed to confirm or rule out abnormal findings. As a result, interpretation of thyroid function tests is now generally straightforward, and more than 90% of people investigated are diagnosed with normal thyroid gland function.
A 66yearold man with abnormal thyroid function tests. Interpretation is a topic covered in the harriet lane handbook to view the entire topic, please sign in or purchase a subscription the harriet lane handbook app and website provides pediatric diagnosis and treatment, pediatric management algorithms, and pediatric drug formulary from experts at johns hopkins university. Tests to evaluate thyroid function include the following. Tsh tests the best way to initially test thyroid function is to measure the tsh level in a blood sample. Thyroid disease who is at risk all newborns neonatal screening personal history of thyroid disease strong family history of thyroid disease have an autoimmune disease, such as type 1 diabetes downs syndrome past history of neck irradiation drug therapies such as lithium and amiodarone women over. Data from thyroid function testing were obtained from the laboratory database of the department of nuclear medicine. A better understanding of the complex nature of the tshft4 relationship may. The thyroids job is to make thyroid hormones, which are secreted into the blood and then carried to every tissue in the body. Thyroid disorders can be difficult to detect clinically, but thyroid function tests can assist in making a diagnosis. Haemoglobin, creatinine, and electrolytes, liver enzymes, glucose, inflammatory markers, and thyroid function tests. Specific considerations when interpreting tfts clinical contextthyroid status.
Knowledge of this thyroid physiology is important in knowing what thyroid test or tests are needed to diagnose different diseases. Interpretation of laboratory thyroid function tests the hidden health problem dr. Clinical strategies in the testing of thyroid function endotext. Thyroid function tests are performed by essentially all medical practitioners across every clinical setting. Plasma free thyroid hormones correlates more closely with thyroid status than plasma total thyroid hormones, which are heavily influenced by changes in plasma tbg. Ppt interpretation of abnormal liver function tests. Interpreting thyroid test results womens health network. Diagnosing unsuspected hypopituitarism in adults from.
Algorithms thyroid disease managerthyroid disease manager. Thyroid function test ppt authorstream presentation. Clinical examination a comprehensive collection of clinical examination osce guides that include stepbystep images of key steps. Interpretation of thyroid tests common tests to examine. The ability to interpret thyroid function tests tfts first requires an understanding of the thyroid hormonal axis. Worlds best powerpoint templates crystalgraphics offers more powerpoint templates than anyone else in the world, with over 4 million to choose from. Scintigraphic manifestations of thyrotoxicosis radiographics. Thyroid function tests are a series of blood tests used to measure how well your thyroid gland is working. The term sick euthyroid is used in this condition since it represents a state of thyroid function appropriate for a sick individual. Interpretation of laboratory thyroid function tests ppt. The major thyroid hormone secreted by the thyroid gland is thyroxine, also called t4 because it contains four iodine atoms.
Nti or sick euthyroid syndrome is a relatively common finding following any acute or chronic illness, and is defined by the absence of. Measuring thyroid stimulating hormone is the first step. T4 concentration is affected by nonthyroidal illness nti and certain medications e. Interpretation thyroidstimulating hormone tsh this test is used to identify. The synthetic pathways of thyroxine t 4 and triiodothyronine t 3, along with the sites of action of antithyroid drugs, are summarised in fig 2. The initially thyroidstimulating hormone tsh blood test is used to check for thyroid gland problems. The tsh alone first line approach to thyroid function testing has. While t4 is the most widely used initial screening test for thyroid disorders, relying on this test alone is a primary reason for the misdiagnosis of canine and feline thyroid disorders. Thyroid function tests tfts are a commonly requested investigation in clinical practice. This guide aims to provide you with the knowledge needed to interpret tfts and consider underlying pathology. Abnormal thyroid function tests thyroid hormone release thyroid hormone metabolism tfts tsh tfts in the sick hyperthyroidism high t4t3, suppressed tsh differential. This chapter is designed to provide an overview of common laboratory tests used in clinical practice. Her medical history is unremarkable and she reports no recent stress, infection, or weight loss.
Thyroid hormones and thyroid function tests youtube. The initially thyroid stimulating hormone tsh blood test is used to check for thyroid gland problems. However, when free t4 is estimated, assay results often need to be evaluated in. Theyll give your presentations a professional, memorable appearance the kind of sophisticated look that todays audiences expect. The most active thyroid hormone triiodothyronine, t3, is largely produced by peripheral ie. Complex relationship between free thyroxine and tsh in the. Click on one of the topics to identify a pathway that will be useful in managing your patient. In patients with acute illness, it is recommended that thyroid function not be assessed unless there is a strong indication. Thyroid function tests american thyroid association. A raised concentration of thyroid stimulating hormone with a low concentration of free thyroxine suggests hypothyroidism. Thyroid function test interpretation tft interpretation.
Topic in focus interpretation of thyroid function tests cmi. Interpreting thyroid function tests powerpoint ppt presentation. Topic in focus interpretation of thyroid function tests. The ability to interpret thyroid function tests tfts first requires. The primary screening test for thyroid dysfunction is serum tsh testing. Pregnancy and thyroid function in pregnancy, there is increased level of t4 and a corresponding decrease in tsh level. Interpretation of laboratory thyroid function tests authorstream presentation. The following algorithms are presented as guides to help direct investigation, diagnosis, and therapy. To perform a thyroid function test, a blood sample is drawn from a vein in your arm and collected in a. A common pitfall in the interpretation of thyroid function tests is to overlook the confounding effects of nonthyroidal illness nti.
Although thyroid disease in its most florid form is easily recognised, patients often manifest symptoms andor signs that are nonspecific, and present to clinicians in many different specialties. If it is abnormal, free thyroxine should be measured. Diagnostic imaging of the thyroid further aids the clinician in determining the underlying cause. The thyroid gland is a butterflyshaped endocrine gland that is normally located in the lower front of the neck. Pitfalls in the measurement and interpretation of thyroid. The most frequently used tests such as complete blood count cbc, electrolytes and blood chemistries, and urinalysis ua are provided first, followed by other clinical and diagnostic tests grouped by disease state or body system. We did not consider abnormal thyroid stimulating hormone concentrations in isolation when arriving at a diagnosis. An overview of the synthesis, regulation, and function of thyroid hormones, as well as the interpretation of thyroid function tests. Regardless, the correct underlying cause must be determined for appropriate management and therapy. Thyroid function tests article about thyroid function. Disorders of thyroid function are common estimated uk prevalence is 14%. The addition of a free t4 measurement will overcome these limitations and diagnose the majority of thyroid functional problems. As a general rule, thyroid function tests should only be requested when there are specific clinical features that require a primary disorder of hypothalamicpituitarythyroid function to be ascertained. How to interpret thyroid function tests rcp journals.
How to test, interpret thyroid function veterinary. Hypopituitarism is a condition in which secretion of pituitary hormones is inappropriately reduced. It is a rare condition, the incidence of which has been estimated at 4. Laboratory tests interpretation nurses learning network.
The expected effects of amiodarone treatment on individual biochemical parameters of thyroid function are outlined below and summarised in table 1, along with a simplified. In the patients with obvious features of hypothyroidism or hyperthyroidism thyroid function tests only confirm the diagnosis. However, while interpreting thyroid function tests, one should not for get subclinical hypothyroidism in which tsh is raised while ft4 and ft3 are within normal range. However, important pitfalls and difficult cases still exist. Thyroid disease who is at risk all newborns neonatal screening personal history of thyroid disease strong family history of thyroid disease have an autoimmune disease, such as type 1 diabetes downs syndrome past history of neck irradiation drug therapies such as lithium and amiodarone women over age 35. Managment of thyroid disease will always require your knowledge and your thought.
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