CSMLS - Canadian Society for Medical Laboratory Science Clinical Chemistry: Endocrinology Questions and Answers

Question 1

A patient presents with hypertension, headaches, and palpitations.
The physician suspects a pheochromocytoma.
Which of the following laboratory tests is considered the most sensitive for confirming this diagnosis?

Accepted Answer

Plasma free metanephrines

Answer

Urinary vanillylmandelic acid (VMA)

Answer

Plasma catecholamines

Answer

Total urinary catecholamines

Question 2

A patient is diagnosed with Graves' disease. What is the characteristic pattern of thyroid function test results expected in this patient?

Accepted Answer

Low TSH, High Free T4

Answer

High TSH, High Free T4

Answer

Low TSH, Low Free T4

Answer

High TSH, Low Free T4

Question 3

A newborn screening test for congenital adrenal hyperplasia (CAH) is positive. Which analyte is typically measured and expected to be significantly elevated in the most common form of CAH, 21-hydroxylase deficiency?

Accepted Answer

17-hydroxyprogesterone

Answer

Cortisol

Answer

Androstenedione

Answer

Deoxycorticosterone

Question 4

A physician is evaluating a patient for Cushing's syndrome. Which of the following initial screening tests would be most appropriate to order?

Accepted Answer

24-hour urinary free cortisol

Answer

Random serum cortisol

Answer

High-dose dexamethasone suppression test

Answer

Serum ACTH

Question 5

A patient is admitted with severe hyponatremia, low serum osmolality, and inappropriately concentrated urine (high urine osmolality). The patient is euvolemic. These findings are most consistent with which of the following conditions?

Accepted Answer

Syndrome of Inappropriate Antidiuretic Hormone (SIADH)

Answer

Diabetes Mellitus

Answer

Adrenal Insufficiency

Answer

Diabetes Insipidus (DI)

Question 6

Which of the following is an important pre-analytical consideration when interpreting thyroid function tests during pregnancy?

Accepted Answer

Trimester-specific reference intervals should be used for TSH and free T4.

Answer

TSH levels are expected to be higher throughout pregnancy.

Answer

Only total T4 should be used as free T4 is unreliable.

Answer

Thyroid peroxidase antibodies are always negative in a normal pregnancy.

A patient presents with hypertension, headaches, and palpitations.The physician suspects a pheochromocytoma.Which of the following laboratory tests is considered the most sensitive for confirming this diagnosis?

A patient presents with hypertension, headaches, and palpitations.
The physician suspects a pheochromocytoma.
Which of the following laboratory tests is considered the most sensitive for confirming this diagnosis?