To evaluate thyroid gland function related to the primary cause of hypothyroidism and assess for congenital disorders, tumor, and inflammation.
Serum collected in a gold-red- or tiger-top tube; for a neonate, use filter paper.
|Age||Conventional Units||SI Units (Conventional Units × 1)|
|Neonates–3 d||Less than 40 micro-international units/mL||Less than 40 milli-international units/L|
|2 wk–5 mo||1.7–9.1 micro-international units/mL||1.7–9.1 milli-international units/L|
|6 mo–1 yr||0.7–6.4 micro-international units/mL||0.7–6.4 milli-international units/L|
|2 yr–19 yr||0.5–4.5 micro-international units/mL||0.5–4.5 milli-international units/L|
|Greater than 20 yr||0.4–4.2 micro-international units/mL||0.4–4.2 milli-international units/L|
|First trimester||0.3–2.7 micro-international units/mL||0.3–2.7 milli-international units/L|
|Second trimester||0.5–2.7 micro-international units/mL||0.5–2.7 milli-international units/L|
|Third trimester||0.4–2.9 micro-international units/mL||0.4–2.9 milli-international units/L|
DescriptionThyroid-stimulating hormone (TSH) is produced by the pituitary gland in response to stimulation by thyrotropin-releasing hormone (TRH), a hypothalamic-releasing factor. TRH regulates the release and circulating levels of thyroid hormones in response to variables such as cold, stress, and increased metabolic need. Thyroid and pituitary function can be evaluated by TSH measurement. TSH exhibits diurnal variation, peaking between midnight and 0400 and troughing between 1700 and 1800. TSH values are high at birth but reach adult levels in the first week of life. Elevated TSH levels combined with decreased thyroxine (T4) levels indicate hypothyroidism and thyroid gland dysfunction. In general, decreased TSH and T4 levels indicate secondary congenital hypothyroidism and pituitary hypothalamic dysfunction. A normal TSH level and a depressed T4 level may indicate (1) hypothyroidism owing to a congenital defect in T4-binding globulin or (2) transient congenital hypothyroidism owing to hypoxia or prematurity. Early diagnosis and treatment in the neonate are crucial for the prevention of congenital hypothyroidism (cretinism).
This procedure is contraindicated forN/A
- Assist in the diagnosis of congenital hypothyroidism.
- Assist in the diagnosis of hypothyroidism or hyperthyroidism or suspected pituitary or hypothalamic dysfunction.
- Differentiate functional euthyroidism from true hypothyroidism in debilitated individuals.
A decrease in thyroid hormone levels activates the feedback loop to increase production of TSH.
- Congenital hypothyroidism in the neonate (filter paper test)
- Ectopic TSH-producing tumors (lung, breast)
- Primary hypothyroidism (related to a dysfunctional thyroid gland)
- Secondary hyperthyroidism owing to pituitary hyperactivity
- Thyroid hormone resistance
- Thyroiditis (Hashimoto’s autoimmune disease)
An increase in thyroid hormone levels activates the feedback loop to decrease production of TSH.
- Excessive thyroid hormone replacement
- Graves’ disease
- Primary hyperthyroidism
- Secondary hypothyroidism (related to pituitary involvement that decreases production of TSH)
- Tertiary hypothyroidism (related to hypothalamic involvement that decreases production of TRH)
- Drugs and other substances that may increase TSH levels include amiodarone, benserazide, erythrosine, flunarizine (males), iobenzamic acid, iodides, lithium, methimazole, metoclopramide, morphine, propranolol, radiographic medium, TRH, and valproic acid.
- Drugs and other substances that may decrease TSH levels include acetylsalicylic acid, amiodarone, anabolic steroids, carbamazepine, corticosteroids, glucocorticoids, hydrocortisone, interferon-alfa-2b, iodamide, levodopa (in hypothyroidism), levothyroxine, methergoline, nifedipine, T4, and triiodothyronine (T3).
- Failure to let the filter paper sample dry may affect test results.
Nursing Implications Procedure
- Related tests include albumin, antibodies antithyroglobulin, biopsy thyroid, copper, newborn screening, PTH, protein, RAIU, thyroglobulin, TSI, TBII, thyroid scan, T4, free T4, T3, free T3, and US thyroid.
- Refer to the Endocrine System Table for related test by body system.
Potential Nursing Problems
|Problem||Signs & Symptoms||Interventions|
|Nutrition (related to slow metabolism)||Decreased appetite with weight gain; selection of high-calorie, high-sodium foods; sedentary lifestyle; caloric intake greater than metabolic needs; constipation; decreased activity||Teach the patient to avoid foods with high sodium, saturated fat, and cholesterol content; teach the patient to eat a diet high in protein and low in calories to promote weight loss; encourage the patient to eat small, frequent meals to prevent overeating and enhance weight control; encourage the consumption of high-fiber foods such as fruits and vegetables with the skins and whole-grain breads to improve gastric motility; monitor daily weight; accurately assess appetite and measure caloric intake over a 24-hr period; arrange dietary consult|
|Decreased cardiac output (related to a deficit of thyroid hormone)||Bradycardia; lethargy; hypotension; decreased thyroid hormone levels; fatigue; activity intolerance; poor peripheral perfusion; cool skin; shortness of breath||Assess and trend vital signs and blood pressure; monitor and trend thyroid laboratory studies (TSH, T3, T4, radioactive iodine uptake); assess cardiac status indicators (peripheral pulses, skin color, skin temperature, dry scaly skin); assess for periorbital edema; administer prescribed thyroid hormone replacement medication; facilitate measures to improve patient warmth (blankets, warm clothing and liquids, warmer environment); pace activity and schedule rest periods to manage fatigue; use pulse oximetry to monitor oxygen saturation; assess respiratory status checking for crackles and increased respiratory rate; monitor for fluid overload|
|Altered thought processes (related to decreased cardiac output and impaired cerebral perfusion secondary to a deficit of thyroid hormone)||Altered memory; mental impairment; decreased concentration; depression; inaccurate environmental perception; inappropriate thinking; memory deficits||Minimize apprehension and dread; collaborate with the health-care provider (HCP) to manage medical problem associated with decreased cerebral perfusion; promote comprehension and understanding of current events; provide a modified environment that promotes safety; monitor the ability to provide self-care (activities of daily living); monitor injury risk (violence, fall risk, self-harm risk); administer prescribed thyroid hormone replacement medication|
|Self-esteem (related to chronic illness; physiologic impairment associated with thyroid hormone deficiency)||Negative self-evaluation; negative evaluation of personal abilities; expressions of shame or guilt; seeks excessive reassurance; exaggerates negative feedback; indecisive; passive; nonassertive; conforming||Facilitate a positive outlook based on real rather than exaggerated factors that influence health; facilitate acknowledgment of personal strengths and values; provide a safe environment for verbalization of concerns; collaborate with patient in designing an appropriate plan of care; collaborate with patient in promoting effective decision making; monitor frequency of negative self-comments; promote the concept of counseling to improve the concept of self-worth; use role-play and modeling to improve positive behavioral skills; provide information about community resources for continued counseling|
- Positively identify the patient using at least two person-specific identifiers before services, treatments, or procedures are performed.
- Patient Teaching: Inform the patient this test can assist in evaluating thyroid function.
- Obtain a history of the patient’s health concerns, symptoms, surgical procedures, and results of previously performed laboratory and diagnostic studies. Include a list of known allergens, especially allergies or sensitivities to latex.
- Obtain a list of the patient’s current medications, including over-the-counter medications and dietary supplements (see Effects of Dietary Supplements online at DavisPlus).
- Review the procedure with the patient. Inform the patient that specimen collection takes approximately 5 to 10 min. Address concerns about pain and explain that there may be some discomfort during the venipuncture.
- Sensitivity to social and cultural issues, as well as concern for modesty, is important in providing psychological support before, during, and after the procedure.
- Note that there are no food, fluid, or medication restrictions unless by medical direction.
- Avoid the use of equipment containing latex if the patient has a history of allergic reaction to latex.
- Instruct the patient to cooperate fully and to follow directions. Direct the patient to breathe normally and to avoid unnecessary movement.
- Observe standard precautions, and follow the general guidelines in Patient Preparation and Specimen Collection online at DavisPlus. Positively identify the patient, and label the appropriate specimen container with the corresponding patient demographics, initials of the person collecting the specimen, date, and time of collection. Perform a venipuncture.
- Remove the needle and apply direct pressure with dry gauze to stop bleeding. Observe/assess venipuncture site for bleeding or hematoma formation and secure gauze with adhesive bandage.
- Promptly transport the specimen to the laboratory for processing and analysis.
Filter Paper Test (Neonate)
- Obtain kit and cleanse heel with antiseptic. Observe standard precautions, and follow the general guidelines in Patient Preparation and Specimen Collection online at DavisPlus. Perform heel stick, gently squeeze infant’s heel, and touch filter paper to the puncture site. Use gauze to dry the stick area completely. When collecting samples for newborn screening, it is important to apply each blood drop to the correct side of the filter paper card and fill each circle with a single application of blood. Overfilling or underfilling the circles will cause the specimen card to be rejected by the testing facility. Additional information is required on newborn screening cards and may vary by testing facility. Newborn screening cards should be allowed to air dry for several hours on a level, nonabsorbent, unenclosed area. If multiple patients are tested, do not stack cards. Testing facility regulations usually require the specimen cards to be submitted within 24 hr of collection.
- Inform the patient that a report of the results will be made available to the requesting HCP, who will discuss the results with the patient.
- Depending on the results of this procedure, additional testing may be performed to evaluate or monitor progression of the disease process and determine the need for a change in therapy. Evaluate test results in relation to the patient’s symptoms and other tests performed.
- Reinforce information given by the patient’s HCP regarding further testing, treatment, or referral to another HCP.
- Recognize anxiety related to test results and answer any questions or address any concerns voiced by the patient or family.
- Educate the patient and family regarding the effects of hypothyroidism on the body over time.
- Educate the family regarding safety interventions that can be taken in the event that the patient becomes confused.
Expected Patient Outcomes:
- The patient and family agree to report to the HCP when the patient experiences difficulty breathing, to facilitate timely interventions.
- The patient and family state the importance of taking thyroid replacement therapy to overall health.
- The patient and family demonstrate proficiency in designing a dietary strategy that encompasses the concept of six small meals a day to better manage caloric needs.
- The patient and family identify ways to conserve energy and prevent fatigue associated with compromised cardiac status.
- The patient complies with the HCP’s recommendation of a dietary consult to assist in managing caloric needs appropriately.
- The patient complies with taking thyroid replacement medication as prescribed.
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