Free Clinical Biochemistry MCQs with Answers

• A. Phosphosphingosides
• B. Phosphoinositides
• C. Glycerophosphatides
• D. Glycerosphingosides

Explanation: Niemann-Pick disease types A and B result from sphingomyelinase deficiency, causing sphingomyelin, a phosphosphingoside, to accumulate in…

• A. >135 mmol/L
• B. < 135 mmol/L
• C. < 160 mmo/L
• D. < 100 mmo/L

Explanation: Hyponatremia means a serum sodium concentration below 135 mmol/L. Values above this threshold are not hyponatremic, while below 100 mmol/L…

• A. Carbohydrates
• B. Micronutrients
• C. Fats
• D. Fibres

Explanation: Parenteral nutrition supplies carbohydrates, lipid-based fats, amino acids, water, electrolytes, vitamins and trace elements…

• A. 1-4 Bodansky units
• B. 1000-4000 Bodansky units
• C. 0.1-0.4 Bodansky units
• D. 100-400 Bodansky units

Explanation: The classical normal serum alkaline-phosphatase range is approximately 1 to 4 Bodansky units, making 1 to 4 the matching option.

• A. 300 to 320
• B. 280 to 295
• C. 350 to 375
• D. 200 to 250

Explanation: Normal plasma or serum osmolality is approximately 280 to 295 mOsm/kg, often rounded similarly in questions using mOsm/L.

• A. Kidney
• B. Liver
• C. Spleen
• D. Bone marrow

Explanation: Heme is broken down mainly by macrophages of the reticuloendothelial system, especially those in the spleen, forming biliverdin and then…

• A. 1-2 mgm%
• B. 7-9 mgm%
• C. 40-50 mgm%
• D. 2.5 - 4.5 mgm%

Explanation: Normal adult serum phosphate is approximately 2.5 to 4.5 mg/dL, also written as mg%.

• A. Potassium
• B. Protein
• C. Urea
• D. Phosphate

Explanation: Potassium is the principal intracellular cation and, with its accompanying anions, contributes greatly to intracellular osmolality.

• A. Myocardial infarction
• B. Muscular dystrophy
• C. Alcoholic cirrhosis
• D. Brain tumours

Explanation: CK-3 corresponds mainly to the CK-MM isoenzyme found in skeletal muscle, so it rises in muscular dystrophy and other skeletal-muscle…

• A. 4-6 mg/dl
• B. 9-11 mg/dl
• C. 19-21 mg/dl
• D. 20-30 mg/dl

Explanation: Normal total serum calcium is approximately 8.5-10.5 mg/dL, making 9-11 mg/dL the closest listed range.

• A. 2.8-3.8 meq/L
• B. 6-7.2 meq/L
• C. 5-5.8 meq/L
• D. 3.8-5 meq/L

Explanation: Normal serum potassium is roughly 3.5-5.0 mEq/L, with many references giving 3.8-5.0 mEq/L.

• A. Transferrin
• B. Ferritin
• C. Hemoglobin
• D. Ceruloplasmin

Explanation: Transferrin is the main plasma protein that binds and transports iron. Ferritin stores iron mainly inside cells, while haemoglobin carries…

• A. Albumin
• B. Firbinogen
• C. Lecithin
• D. Globulin

Explanation: Fibrinogen is present in plasma but removed during clot formation, so it is absent from serum.

• A. Phenyl lactate
• B. 3- Hydroxy phenyl pyruvate
• C. 5- Hydroxy indole acetate
• D. Phenyl acetate

Explanation: Argentaffinoma, commonly associated with a serotonin-secreting carcinoid tumour, produces excess serotonin that is metabolised to…

• A. Boiling test
• B. Hay's test
• C. Barfoed test
• D. Ehrlich's test

Explanation: The boiling test detects urinary protein because proteins coagulate on heating, producing turbidity or a precipitate.

• A. All of the above
• B. Ornithine
• C. Arginine
• D. Lysine
• E. Cystine

Explanation: Cystinosis causes a proximal tubular reabsorption defect with generalised aminoaciduria, including cystine, ornithine, arginine and…

• A. Histidine
• B. Cystine
• C. Tyrosine
• D. Alanine

Explanation: Albinism commonly results from deficient tyrosinase activity, which disrupts the conversion of tyrosine into melanin.

• A. Leucine
• B. Isoleucine
• C. Valine
• D. All of the above

Explanation: Maple syrup urine disease results from deficiency of the branched-chain alpha-ketoacid dehydrogenase complex, causing leucine, isoleucine…

• A. Low platelet count
• B. Increased prothrombin time
• C. Decreased prothrombin time
• D. None of the above

Explanation: Vitamin K is needed to produce functional clotting factors, so deficiency prolongs the prothrombin time.