Chemistry-endocrinology and tumor markers

b

TSH produced by pituitary gland

TSH is produced by the:

a. hypothalamus

b. pituitary gland

c. adrenal cortex

d. thyroid

b

Increased TSH, decreased free T4 and total T4, positive microsomal Ab consistent with primary hypothyroidism

A patient has the following thyroid profile:

total T4: decreased

free T4: decreased

thyroid peroxidase antibody: positive

TSH: increased

This patient most probably has:

a. hyperthyroidism

b. hypothyroidism

c. a normal thyroid

d. Graves disease

d

Increased TSH, decreased free T4 and total T4, symptoms of cold intolerance and hair loss are consistent with hypothyroidism

A 45 yr old woman complains of fatigue, heat intolerance and hair loss. Total and free T4 are abnormally low. If the TSH showed marked elevation, this would be consistent with:

a. Graves disease

b. an adenoma of the thyroid

c. thyrotoxicosis

d. primary hypothyroidism

c

T3 is more biologically active, 80% of T4 is converted to T3

The majority of thyroxine (T4) is converted into the more biologically active hormone:

a. thyroglobulin

b. thyroid-stimulating hormone (TSH)

c. triiodothyronine (T3)

d. thyrotropin-releasing hormone

b

Congenital hypothyroidism presents with very low thyroid hormones and is best confirmed by serum TSH

A 2 yr old child with a decreased serum T4 is described as being somewhat dwarfed, stocky, overweight, and having coarse features. Of the following, the most informative additional laboratory test would be the serum:

a. thyroxine binding globulin (TBG)

b. thyroid-stimulating hormone (TSH)

c. triiodothyronine (T3)

d. cholesterol

b

>99% of T3 and T4 are bound to thyroxine-binding prealbumin, thyroxine-binding globulin, and albumin

Assays for free T4 measure hormone not bound to thyroxine-binding prealbumin, thyroxine-binding globulin and:

a. thyrotropin-releasing hormone

b. albumin

c. free T3

d. thyroid stimulating hormone

b

TSH is the American Thyroid Association's recommended screening test

The recommended initial thyroid function test for either a healthy, asymptomatic patient or a patient with symptoms which may be related to a thyroid disorder is:

a. free thyroxine (free T4)

b. thyroid-stimulating hormone (TSH)

c. total thyroxine (T4)

d. triiodothyronine (T3)

d

Neonates are screened using total T4

The screening test for congenital hypothyroidism is based upon:

a. TSH level in the newborn

b. thyroid-binding globulin level in the newborn

c. iodine level in the newborn

d. total thyroxine (T4) level in the newborn

d

Hashimoto thyroiditis-the most common cause of hypothyroidism

Which one of the following sets of results is consistent with primary hypothyroidism (eg. Hashimoto thyroiditis):

Result TSH T4 (free thyroxine) Antimicrosomal antibody

result A:decreased decreased positive

resultB: increased increased positive

resultC: normal decreased negative

resultD: increased decreased positive

a. result A

b. result B

c. result C

d. result D

a

Age, sex, physical complaint, with elevated TSH point to primary hypothyroidism

A 68 yr old female patient tells her physician of being "cold all the time" and recent weight gain, with no change in diet. The doctor orders a TSH level, and the laboratory reports a value of 8.7 uU/ml (8.7 IU/L) (reference range = 0.5-5.0 uU/mL [0.5-5.0 IU/L)]. This patient most likely has:

a. primary hypothyroidism

b. Graves disease

c. a TSH-secreting tumor

d. primary hyperthyroidism

b

hCG is the primary marker for early pregnancy

Which of the following is secreted by the placenta and used for the early detection of pregnancy?

a. follicle - stimulating hormone (FSH)

b. human chorionic gonadotropin (HCG)

c. luteinizing hormone (LH)

d. progesterone

b

During pregnancy, the largest fraction of estrogen in urine is estriol

During pregnancy, the form of estrogen measured in urine is mostly:

a. estradiol

b. estriol

c. estrone

d. pregnanediol

b

hCG levels peak at 8-10 weeks after the last menstrual period (LMP)

Refer to the question on pg 122 #223

a

The procedure "change in absorbance of amniotic fluid at 450 nm" used to detect hemolytic disease of newborn (HDN)

In amniotic fluid, the procedure used to detect hemolytic disease of the newborn is:

a. measurement of absorbance at 450 nm

b. creatinine

c. lecithin/sphingomyelin ratio

d. estriol

b

Serum hCG levels peak at 8-10 weeks

During a normal pregnancy, quantitative human chorionic gonadotropin (HCG) levels peak how many weeks after the last menstrual period?

a. 2-4

b. 8-10

c. 14-16

d. 18-20

a

MoM calc= 34/32=1.06 (or <2)

"Laboratory A" measures maternal serum alpha-fetoprotein (MSAFP) at 16-18 weeks gestation as a screen for fetal disorders. The 16 week MSAFP median for Lab A is 32 ug/L. A 37 year old woman has an MSAFP level of 34 ug/L at her 16th week. This result is consistent with:

a. a normal MSAFT level for 16 week gestation

b. possible neural tube defect, including spina bifida

c. possible multiple birth (ie, twins)

d. possible trisomy disorder, including Down syndrome

b

Aldosterone is a hormone produced by the adrenal cortex

Which of the following steroids is an adrenal cortical hormone?

a. angiotensinogen

b. aldosterone

c. epinephrine

d. growth hormone

d

All adrenal steroid hormones are enzymatically derived from cholesterol.

What common substrate is used in the biosynthesis of adrenal steroids, including androgens and estrogens?

a. cortisol

b. catecholamines

c. progesterone

d. cholesterol

d

Testosterone is the most biologically active androgen in the embryonic stage and later effects sperm production and secondary sex characteristics

The biologically most active, naturally occurring androgen is:

a. androstenedione

b. cortisol

c. epiandrosterone

d. testosterone

a

The normal variation of serum cortisol is higher at 8 am than 4pm

Plasma for cortisol determination were collected at 7 am, after waking the patient, and at 10 pm that evening. The cortisol level of the morning sample was higher than the evening sample. This is consistent with:

a. a normal finding

b. Cushing syndrome

c. Addison disease

d. hypopituitarism

a

A deficiency of vitamin A leads to night blindness, and if prolonged total blindness

Night blindness is associated with deficiency of which of the following vitamins?

a. A

b. C

c. niacin

d. thiamine

d

A deficiency of thiamine (vitamin B1) known as beriberi, may be seen with chronic alcoholism in the US

Beriberi is associated with deficiency of vitamin:

a. A

b. C

c. niacin

d. thiamine

b

A deficiency of ascorbic acid (vitamine C) is called scurvy

Scurvy is associated wit deficiency of which of the following vitamins?

a. A

b. C

c. niacin

d. thiamine

d

A deficiency of vitamin D in children leads to rickets

Rickets is associated with deficiency of which of the following vitamins?

a. B1

b. C

c. niacin

d. D

d

A deficiency of niacin may be seen with chronic alcoholism, and is known as pellagra

Pellagra is associated with deficiency of which of the following vitamins?

a. A

b. B1

c. thiamine

d. niacin

b

Angiotensin II is a vasoconstrictor and stimulates the adrenal cortex to produce aldosterone.

The major action of angiotensin II is:

a. increased pituitary secretion of vasopressin

b. increased vasoconstriction

c. increased parathormone secretion by the parathyroid

d. decreased adrenal secretion of aldosterone

d

Vanilylmandelic acid (VMA) is the major metabolite of epinephrine and norepinephrine. VMA is measured in a 24-hr urine

The urinary excretion product measured as an indicator of epinephrine production is:

a. dopamine

b. dihydroxyphenylalanine (DOPA)

c. homovanillic acid

d. vanillylmandelic acid (VMA)

c

Parathyroid hormone (PTH) and the hormone vitamin D play a dominant role in calcium regulation.

Which of the following hormones regulates normal blood calcium levels?

a. thyroxine

b. estriol

c. parathyroid hormone

d. growth hormone

c

95% of congenital adrenal hyperplasia is associated with a deficiency of 21-hydroxylase. Increased 17-OH progesterone is seen if measured by the laboratory.

The most common form (95%) of congenital adrenal hyperplasia is 21-hydroxylase deficiency, which is detected by elevated plasma:

a. cortisol

b. aldosterone

c. 17-OH-progesterone

d. 11-deoxycortisol

c

ACTH stimulation tests, using synthetic ACTH, will differentiate primary from secondary adrenal insufficiency. Synthetic ACTH will not cause the adrenal gland to respond in primary insufficiency.

A diagnosis of primary adrenal insufficiency requires demonstration of:

a. decreased urinary 17-keto- and 17-hydroxysteroids

b. decreased cortisol production

c. impaired response to ACTH stimulation

d. increased urinary cortisol excretion after metyrapone

a

The 24 hr urine free cortisol is the most sensitive and specific screen for hypercortisolism

The screen for adrenal cortical hyperfunction with the greatest sensitivity and specificity is:

a. 24 hr urine free cortisol

b. plasma cortisol

c. urinary 17-hydroxycorticosteroids

d. plasma corticosterone

c

Following an overnight fast, a 100 gram oral glucose load will cause a large drop in serum growth hormone in a normal individual, but will not suppress in patients with acromegaly

A patient has signs and symptoms suggestive of acromegaly. The diagnosis would be confirmed if the patient had which of the following?

a. an elevated serum phosphate concentration

b. a decreased serum growth hormone releasing factor concentration

c. no decrease in serum growth hormone concentration 90 minutes after oral glucose administration

d. an increased serum somatostatin concentration

b

About 55-60% of patients whose breast tumors demonstrate estrogen receptors (ER) respond well to endocrine therapy

Estrogen and progesterone receptor assays are useful in identifying patients who are likely to benefit from endocrine therapy to treat which of the following?

a. ovarian cancer

b. breast cancer

c. endometriosis

d. amenorrhea

c

Due to circadian variation, the 24 hr UFC is an accurate measurement of active forms of cortisol.

Which of the following sample collections would give an accurate assessment of potential excess cortisol production (hypercortisolism)?

a. collect a plasma sample as a baseline, and another one-hour after administration of metyrapone

b. collect a plasma sample at 8 am only

c. collect a 24 hr urine free cortisol

d. collect a plasma sample at 8 am and at 8 am the next day

b

Primary hpocortisolism = decreased cortisol/elevated ACTH; secondary hypocortisolism = decreased cortisol/decreased ACTH

How is primary hypocortisolism (Addison disease) differentiated from secondary hypocortisolism (of pituitary origin)?

a. adrenal corticotropic hormone (ACTH) is decreased in primary and elevated in secondary

b. ACTH is elevated in primary and decreased in secondary

c. low aldosterone and hypoglycemia present with secondary hypocotisolism

d. normal cortisol levels and blood pressure with primary hypocortisolism

d

Angiotensin II directly stimulates the adrenal cortex to release aldosterone

Aldosterone is released by the adrenal cortex upon stimulation by:

a. renin

b. angiotensinogen

c. angiotensin I

d. angiotensin II

d

Increased CEA levels are seen in patients with liver damage, heavy smokers and following radiation and chemotherapy

In developing the reference for a new EIA for CEA, the range for the normal population was broader than that published by the vendor. Controls are acceptable with a narrow coefficient of variation. This may be explained by:

a. positive interference by another tumor marker

b. population skewed to a younger age

c. improper temperature control during assay

d. inclusion of nonsmokers and smokers in the study population

b

Tumor markers are useful for monitoring therapy, detecting recurrence and aiding in prognosis of tumors, but are not useful for screening the general population for cancer

Clinical assays for tumor markers are most important for:

a. screening for the presence of cancer

b. monitoring the course of a known cancer

c. confirming the absence of disease

d. identifying patients at risk for cancer

a

Most testicular tumors are germ cell tumors which are characterized by elevated serum levels of AFP. Measurement of serum AFP is used in the diagnosis, therapy and follow up of testicular cancer. The carcinoembryonic antigen is a marker for colon cancer. The serum levels of testosterone and prolactin are not increased in testicular cancer.

Detection of which of the following substances is most useful to monitor the course of a patient with testicular cancer?

a. alpha - fetoprotein

b. carcinoembryonic antigen

c. prolactin

d. testosterone

a

AFP is an oncofetal glycoprotein marker for hepatocellular carcinoma. Elevated levels of AFP (<200 ug/L) are seen in hepatitis and cirrhosis. However, in hepatocellular carcinoma, the levels can be greater than 1,000 ug/L.

Increased concentrations of AFP in adults are most characteristically associated with:

a. hepatocellular carcinoma

b. alcoholic cirrhosis

c. chronic active hepatitis

d. multiple myeloma

d

The carcinoembryonic antigen (CEA) is a marker for colon, gastrointestinal and lung cancer. Elevated serum levels of CEA are primarily seen with colon cancer. Although the levels may be increased in individuals with benign conditions, the level of CEA elevation is greater for colon cancer.

Carcinoembryonic antigen (CEA) is most likely to be produced in a malignancy involving the:

a. brain

b. testes

c. bone

d. colon

a

tPSA along with DRE is the recommended screen for prostate cancer in males over 50 yrs of age

Which of the following is useful in the detection and management of carcinoma of the prostate?

a. total prostate-specific antigen

b. prostatic acid phosphatase

c. human chorionic gonadotropin

d. alpha-fetoprotein

d

Markers are good for monitoring therapy and detecting recurrence of tumors

Which of the following statements most correctly describes the utility of clinical laboratory assays for tumor markers?

a. tumor markers are useful to screen asymptomatic patients for tumors

b. tumor markers are highly specific

c. tumor markers indicate the likelihood of an individual developing a tumor

d. tumor markers are useful in tracking the efficacy of treatment

d

CA 125 is elevated in 80% of epithelial cell ovarian cancer

Cancer antigen 125 (CA 125) is a tumor marker associated with:

a. breast carcinoma

b. colon cancer

c. lung cancer

d. ovarian and endometrial carcinoma

c

PSA can be elevated due to BPH

In addition to carcinoma of the prostate, elevated prostate-specific antigen (PSA) can occur due to:

a. aspirin therapy

b. exogenous steroid use

c. benign prostatic hyperplasia

d. statin therapy (cholesterol lowering drug)