CHEMICAL PATH MCQS

Question 1

Which tumor marker is most specific for hepatocellular carcinoma?

Accepted Answer

AFP

Question 2

A patient with small cell lung cancer develops hyponatremia with concentrated urine. The ectopic hormone responsible is:

Accepted Answer

ADH

Question 3

CA 125 is the tumor marker of choice for monitoring treatment response in:

Accepted Answer

Ovarian cancer

Question 4

Which lab finding best distinguishes ectopic ACTH syndrome from pituitary Cushing disease?

Accepted Answer

Very high ACTH with failed high-dose dexamethasone suppression

Question 5

A man with bronchogenic carcinoma has calcium 13.2 mg/dL with suppressed PTH. The mediator is:

Accepted Answer

PTHrP

Question 6

The most common cause of delayed puberty in boys is:

Accepted Answer

Constitutional delay of growth and puberty

Question 7

A 16-year-old girl has no breast development, primary amenorrhea, and elevated FSH/LH. Karyotype is 45,X. Diagnosis:

Accepted Answer

Turner syndrome

Question 8

Precocious puberty in girls is defined as secondary sexual development before age:

Accepted Answer

8 years

Question 9

A 6-year-old boy has pubic hair, enlarged testes, and pubertal LH response to GnRH. Diagnosis:

Accepted Answer

Central precocious puberty

Question 10

The most common cause of hirsutism in reproductive-age women is:

Accepted Answer

Polycystic ovary syndrome

Question 11

Best biochemical marker of adrenal androgen excess in hirsutism:

Accepted Answer

DHEA-S

Question 12

Which feature is NOT part of virilism in women?

Accepted Answer

Galactorrhea

Question 13

Semen analysis: count 10 million/mL, motility 20%, morphology 2%. This is:

Accepted Answer

Oligoasthenoteratozoospermia

Question 14

WHO lower reference limit for normal sperm concentration is:

Accepted Answer

15 million/mL

Question 15

Elevated FSH with azoospermia in a male infertility workup suggests:

Accepted Answer

Primary testicular failure

Question 16

Aminoglycoside trough level sample should be collected:

Accepted Answer

Just before the next dose

Question 17

Which drug has the narrowest therapeutic index requiring routine TDM?

Accepted Answer

Digoxin

Question 18

In acetaminophen toxicity, the antidote N-acetylcysteine works by replenishing:

Accepted Answer

Glutathione

Question 19

Carbon monoxide poisoning is confirmed by measuring:

Accepted Answer

Carboxyhemoglobin

Question 20

In salicylate toxicity, the earliest acid-base disturbance is:

Accepted Answer

Respiratory alkalosis

Question 21

Phenylketonuria results from deficiency of:

Accepted Answer

Phenylalanine hydroxylase

Question 22

The newborn screening test for PKU measures:

Accepted Answer

Serum phenylalanine

Question 23

A patient with dark urine on standing, ochronosis, and arthritis has:

Accepted Answer

Alkaptonuria

Question 24

Maple syrup urine disease involves accumulation of:

Accepted Answer

Branched-chain amino acids

Question 25

Classic galactosemia is due to deficiency of:

Accepted Answer

Galactose-1-phosphate uridyltransferase

Question 26

The gold standard for diagnosing osteoporosis is:

Accepted Answer

DEXA scan

Question 27

In Paget's disease of bone, which marker is most characteristically elevated?

Accepted Answer

Alkaline phosphatase

Question 28

Primary hyperparathyroidism characteristically shows:

Accepted Answer

High calcium, low phosphate, high PTH

Question 29

The enzyme deficient in classic gout leading to hyperuricemia is:

Accepted Answer

Hypoxanthine-guanine phosphoribosyltransferase (HGPRT)

Question 30

Allopurinol treats gout by inhibiting:

Accepted Answer

Xanthine oxidase

Question 31

The hypothalamic hormone that stimulates both FSH and LH release is:

Accepted Answer

GnRH

Question 32

Growth hormone excess before epiphyseal fusion causes:

Accepted Answer

Gigantism

Question 33

The best screening test for acromegaly is:

Accepted Answer

IGF-1

Question 34

Diabetes insipidus is characterized by:

Accepted Answer

Low urine osmolality, high serum osmolality

Question 35

A patient has low TSH and high free T4. The most likely diagnosis is:

Accepted Answer

Primary hyperthyroidism

Question 36

The best initial test to evaluate thyroid function is:

Accepted Answer

TSH

Question 37

Hashimoto's thyroiditis is associated with antibodies against:

Accepted Answer

Thyroglobulin and thyroid peroxidase

Question 38

The HbA1c reflects average blood glucose over the preceding:

Accepted Answer

4 months

Question 39

Diagnostic criterion for diabetes mellitus using fasting plasma glucose is:

Accepted Answer

≥ 7.0 mmol/L

Question 40

In diabetic ketoacidosis, the predominant ketone body measured by nitroprusside test is:

Accepted Answer

Acetoacetate

Question 41

C-peptide measurement helps differentiate type 1 DM from factitious hypoglycemia because:

Accepted Answer

Exogenous insulin suppresses C-peptide

Question 42

The classic triad of Cushing syndrome includes all EXCEPT:

Accepted Answer

Hypoglycemia

Question 43

The best outpatient screening test for Cushing syndrome is:

Accepted Answer

Overnight 1 mg dexamethasone suppression test

Question 44

Primary hyperaldosteronism (Conn syndrome) characteristically presents with:

Accepted Answer

Hypokalemia, hypertension, low renin

Question 45

In congenital adrenal hyperplasia due to 21-hydroxylase deficiency, which metabolite is elevated?

Accepted Answer

17-hydroxyprogesterone

Question 46

The earliest marker of glomerular damage in diabetic nephropathy is:

Accepted Answer

Microalbuminuria

Question 47

Which formula is used to estimate GFR in clinical practice?

Accepted Answer

Cockcroft-Gault or CKD-EPI

Question 48

In nephrotic syndrome, the urine dipstick finding is:

Accepted Answer

4+ proteinuria

Question 49

The most sensitive early indicator of tubular dysfunction is:

Accepted Answer

Urine beta-2 microglobulin

Question 50

In pre-renal acute kidney injury, urine sodium is typically:

Accepted Answer

< 20 mmol/L

CHEMICAL PATH MCQS

Questions, Answers & Explanations