The most active thyroid hormone triiodothyronine, t3, is largely produced by peripheral ie. Scintigraphic manifestations of thyrotoxicosis radiographics. 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. Uk guidelines for the use of thyroid function tests. However, when free t4 is estimated, assay results often need to be evaluated in. The term sick euthyroid is used in this condition since it represents a state of thyroid function appropriate for a sick individual. There are no abnormalities on clinical examination.
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. The tsh alone first line approach to thyroid function testing has. Laboratory tests interpretation nurses learning network. Interpretation of thyroid function tests the lancet. T4 concentration is affected by nonthyroidal illness nti and certain medications e. Interpretation of thyroid function tests sciencedirect. A better understanding of the complex nature of the tshft4 relationship may. Tsh tests the best way to initially test thyroid function is to measure the tsh level in a blood sample. Pregnancy and thyroid function in pregnancy, there is increased level of t4 and a corresponding decrease in tsh level. We wish to acknowledge the generous permission given by drs. Interpretation of laboratory thyroid function tests the hidden health problem dr. Interpreting thyroid function tests powerpoint ppt presentation. 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.
Ppt interpretation of abnormal liver function tests. 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. Loading slideshow in 5 seconds interpreting thyroid function tests powerpoint presentation. Clinical examination a comprehensive collection of clinical examination osce guides that include stepbystep images of key steps.
The ability to interpret thyroid function tests tfts first requires an understanding of the thyroid hormonal axis. The ability to interpret thyroid function tests tfts first requires. Knowledge of this thyroid physiology is important in knowing what thyroid test or tests are needed to diagnose different diseases. The primary screening test for thyroid dysfunction is serum tsh testing. Winner of the standing ovation award for best powerpoint templates from presentations magazine. Clinical strategies in the testing of thyroid function endotext. 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 are performed by essentially all medical practitioners across every clinical setting. Tsh thyroidstimulating hormone tsh is excreted by the pituitary gland and acts to stimulate the production of t4 by the thyroid. Interpretation of laboratory thyroid function tests slideshare.
The initially thyroidstimulating hormone tsh blood test is used to check for thyroid gland problems. Diagnosing unsuspected hypopituitarism in adults from. A 66yearold man with abnormal thyroid function tests. 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. Thyroid function tests article about thyroid function. Thyroid disorders can be difficult to detect clinically, but thyroid function tests can assist in making a diagnosis. Interpreting thyroid test results womens health network. Complex relationship between free thyroxine and tsh in the. Data from thyroid function testing were obtained from the laboratory database of the department of nuclear medicine. Ppt d interpreting thyroid function tests powerpoint. 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. If it is abnormal, free thyroxine should be measured. Some clinicians also measure serum total t 3 level thyroid function testing in critically ill patients usually shows low serum. How to interpret thyroid function tests rcp journals.
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. Haemoglobin, creatinine, and electrolytes, liver enzymes, glucose, inflammatory markers, and thyroid function tests. The following algorithms are presented as guides to help direct investigation, diagnosis, and therapy. The history and physical examination, along with thyroid function tests, enable the clinician to make the diagnosis of thyrotoxicosis. A raised concentration of thyroid stimulating hormone with a low concentration of free thyroxine suggests hypothyroidism. A free powerpoint ppt presentation displayed as a flash slide show on id. Thyroid hormones and thyroid function tests duration. 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. Worlds best powerpoint templates crystalgraphics offers more powerpoint templates than anyone else in the world, with over 4 million to choose from. No one single laboratory test is 100% accurate in diagnosing all types of thyroid disease. Pitfalls in the measurement and interpretation of thyroid. There are several different thyroid function tests.
Abnormal thyroid function tests thyroid hormone release thyroid hormone metabolism tfts tsh tfts in the sick hyperthyroidism high t4t3, suppressed tsh differential. The thyroids job is to make thyroid hormones, which are secreted into the blood and then carried to every tissue in the body. Thyroid function tests are a series of blood tests used to measure how well your thyroid gland is working. Algorithms thyroid disease managerthyroid disease manager. A common pitfall in the interpretation of thyroid function tests is to overlook the confounding effects of nonthyroidal illness nti. Ppt thyroid disease powerpoint presentation free to. Diagnostic imaging of the thyroid further aids the clinician in determining the underlying cause. Topic in focus interpretation of thyroid function tests cmi. Nti or sick euthyroid syndrome is a relatively common finding following any acute or chronic illness, and is defined by the absence of. The results of thyroid function tests tfts must always be interpreted in light of the clinical status of the. 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.
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. Interpretation of laboratory thyroid function tests authorstream presentation. T3 should be added if there is a suggestion of thyrotoxicosis, as it alone may be elevated in some cases of hyperthyroidism. The major thyroid hormone secreted by the thyroid gland is thyroxine, also called t4 because it contains four iodine atoms. This guide aims to provide you with the knowledge needed to interpret tfts and consider underlying pathology. Tests to evaluate thyroid function include the following. It is a rare condition, the incidence of which has been estimated at 4. How to test, interpret thyroid function veterinary.
Her medical history is unremarkable and she reports no recent stress, infection, or weight loss. This test is used to evaluate thyroid function and sometimes used to diagnose fertility problems. 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. Theyll give your presentations a professional, memorable appearance the kind of sophisticated look that todays audiences expect. Thyroid function tests tfts are a commonly requested investigation in clinical practice. Topic in focus interpretation of thyroid function tests. If thyroid function assessment is indicated for critically ill patients, serum tsh and free t 4 concentrations should be measured. Thyroid hormones and thyroid function tests youtube. Thyroid function tests american thyroid association. 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. Hypopituitarism is a condition in which secretion of pituitary hormones is inappropriately reduced. This chapter is designed to provide an overview of common laboratory tests used in clinical practice. In the patients with obvious features of hypothyroidism or hyperthyroidism thyroid function tests only confirm the diagnosis.
Thyroid function tests leeds teaching hospitals nhs trust. Interpretation of laboratory thyroid function tests 1. A collection of guides to interpreting various laboratory tests, including liver function tests lfts, thyroid function tests tfts and more. Disorders of thyroid function are common estimated uk prevalence is 14%. Interpretation of thyroid tests common tests to examine.
Thyroid function test ppt authorstream presentation. Plasma free thyroid hormones correlates more closely with thyroid status than plasma total thyroid hormones, which are heavily influenced by changes in plasma tbg. Thyroid diseases are among the most prevalent of medical conditions. Blood tests to measure tsh, t4 and t3 free t3 and free t4 are readily available and widely used. Specific considerations when interpreting tfts clinical contextthyroid status.
The initially thyroid stimulating hormone tsh blood test is used to check for thyroid gland 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. Ppt interpreting thyroid function tests powerpoint. The addition of a free t4 measurement will overcome these limitations and diagnose the majority of thyroid functional problems. Thyroid function test interpretation tft interpretation. To perform a thyroid function test, a blood sample is drawn from a vein in your arm and collected in a. Interpreting the tests is complicated as there are various conditions that can change the level of thyroid hormones. Multiple tests over 3 to 6 mo should be performed to confirm or rule out abnormal findings. Hussam elmouzi clinical pathologist al borg laboratory 2. Thyroid function tests tft are often abnormal in patients with nonthyroidal illness nti. 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. Interpretation of laboratory thyroid function tests ppt. Interpretation thyroidstimulating hormone tsh this test is used to identify.
An overview of the synthesis, regulation, and function of thyroid hormones, as well as the interpretation of thyroid function tests. Significant insights have been gained into thyroid regulation and thyroid hormone metabolism that influence the selection and interpretation of thyroid function tests. Managment of thyroid disease will always require your knowledge and your thought. Regardless, the correct underlying cause must be determined for appropriate management and therapy. Measuring thyroid stimulating hormone is the first step.
We did not consider abnormal thyroid stimulating hormone concentrations in isolation when arriving at a diagnosis. The thyroid gland is a butterflyshaped endocrine gland that is normally located in the lower front of the neck. Interpretation of laboratory thyroid function tests. 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.
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