Clinical Chemistry II, Quiz 14.

Board Review Question: The TRH (thyrotropin-releasing hormone) stimulation test is useful in assessing which of the following?

hyperthyroidism

Board Review Question: Which of the following methods employs a highly specific antibody to thyroxine?

T4 by RIA

Board Review Question: A patient has the following thyroid profile;

total T4 = increased

free thyroxine index = normal

T3 uptake = decreased

TSH normal

The patient most probably

has increased protein-bound T4

thyroxine

Board Review Question: The T3 uptake test is based on

relative binding of T3 and T4 to globulin

All of the following proteins transport thyroid hormones EXCEPT:

Gamma gobulin

Primary hypothyroidism may be due to which of the following?

all of the above

Thyroid peroxidase autoantibodies are most sensitive for detecting which thyroid disease or condition listed below?

Autoimmune thyroid disease (e.g., Hashimoto's thyroiditis

Serum thyroid stimulating hormone (TSH) levels are decreased in which of the following diseases or conditions?

primary hyperthyriodism

Which of the following tests may be used to differentiate between hypothalamic hypothyroidism and pituitary hypothyroidism?

TH stimulation test

The following laboratory results correlate with which of the following thyroid disorders?

TSH 7.8 mIU/L (0.3-4.2)

T4 0.3 mU/L (0.4-4.0)

FT4 0.5 ng/dL (0.9-1.7)

T3 58 ng/dL (80-200)

TRH 40 pg/mL (<= 40)

Primary hypothyroidism

What are the expected laboratory results in a patient suspected of having Hashimoto's disease?

Decreased T4, increased TSH

Which of the following thyroid tests should be used to screen a 2-year-old child who presents as dwarfed, stocky, overweight, and having coarse features?

Thyroid-stimulating hormone (TSH)

A 35-year-old pregnant female has the following laboratory results. What is the most likely explanation for these results?

TSH 3.4 mIU/L

T4 5.4 mU/L (0.4-4.0)

FT4 1.5 ng/dL (0.9-1.7)

T3 220 ng/dL (80-200)

FT3 3.3 pg/mL (2.8-4.4)

Euthyroidism

Primary, secondary, and tertiary disorders correspond to what endocrine glands respectively?

Target gland, pituitary, hypothalamus

Quantitatively, what is the major fraction of organic iodine circulating in the bloodstream?

Tetraiodothyronine

A patient sample is added to a reaction vessel with anti-T3 monoclonal antibody conjugated to alkaline phosphatase. During incubation, FT3 reacts with anti-T3 antibody. Particles coated with streptavidin and biotinylated T3 analog are added to the reaction vessel. Immune complexes bound to the solid phase are held in a magnetic field, while unbound substances are then removed by a wash step. What is the principle of this FT3 assay?

Competitive binding immunoenzymatic assay

Inhibition of thyrotropin releasing hormone is associated with what hormones produced by the delta cells of the islets of Langerhans?

Somatostatin

Board Review Question: The T3 resin uptake test is a measure of

binding capacity of thyroxine-binding globulin

Board Review Question: A patient's values are as follows:

T4 = 4ug/dL(ref range5-12 ug/dL)

T3 uptake = 40% (ref range 25-35%)

What is the patient's free thyroxine index?

1.6

In the thyroid gland, which of the following is described as the secretory unit?

follicle

Why is the third generation assay needed for TSH in patients with Graves' disease?

The alpha subunit of TSH is identical to FSH, LH, and hCG.

Thyroid hormones are derived from which of the following amino acids?

tyrosine

What are the expected laboratory results in a patient with suspected primary hyperthyroidism?

Increased T4, decreased TSH

In a patient with suspected primary hyperthyroidism (Graves' disease), one would expect the following laboratory serum results: total T 4 ____FT 4____, and TSH_____.

Increased, increased, decreased

The following results were obtained on a patient: free T 4 low, free T 3 low, TSH low. This patient suffers from

secondary or tertiary hypothyroidism

Board Review Question: The major fraction of organic iodine in the circulation is in the form of

thyroxine