Biochemistry and Clinical Pathology Questions and Answers

Answer: A

TFT stands for Thyroid Function Test.

A thyroid function test is a panel of blood tests that measures thyroid-stimulating hormone (TSH) from the pituitary together with the thyroid hormones T3 and T4 (often their free fractions). It is used to diagnose and monitor hypothyroidism and hyperthyroidism.

Triiodothyronine (T3) and thyroxine (T4) are measured within the test, so naming the test after only one of them is wrong. Testosterone is a sex hormone and has nothing to do with the thyroid.

Answer: B

The keyed test is the renal function test.

Abnormal constituents of urine, such as protein, glucose, blood, ketone bodies and casts, are looked for in urine examination, which forms part of the work-up of kidney function along with blood urea and serum creatinine.

The other options examine different organs. Gastric juice analysis studies stomach acid secretion. A cardiac profile measures heart markers such as troponin and CK-MB in blood. Pancreatic enzyme tests measure amylase and lipase. None of them is aimed at urine constituents.

Answer: C

The white blood cell count is also known as the Total Leukocyte Count (TLC).

The question asks about the count, the laboratory test that gives the number of white cells per microlitre of blood (normally about 4,000 to 11,000 in adults). That test is the TLC.

'Leukocytes' is the name of the white cells themselves, not of their count, which is the trap in option B. Erythrocytes are red blood cells and thrombocytes are platelets.

Answer: B

The correct sequence is Vascular Spasm → Platelet Plug Formation → Blood Clotting (Coagulation).

When a vessel is cut, its smooth muscle contracts at once (vascular spasm), narrowing the vessel and reducing blood loss within seconds. Platelets then stick to the exposed collagen, release chemicals that attract more platelets, and form a temporary plug. Finally the coagulation cascade turns fibrinogen into fibrin, which reinforces the plug into a stable clot.

Every other order puts a slower step first. Coagulation takes minutes and depends on platelets already being in place, so it cannot come first, and the platelet plug forms after the vessel has constricted.

Answer: A

Haemoglobin is measured in grams per decilitre (g/dL).

Haemoglobin is present in large amounts, about 13 to 17 g/dL in adult men and 12 to 15 g/dL in adult women, so it is reported in grams per 100 mL of blood.

Milligrams alone is a mass, not a concentration. Milligrams per decilitre is used for substances present in far smaller amounts, such as glucose or creatinine. Kilograms per decilitre would be a thousand times too large for any blood constituent.

Answer: B

The one that is not a branch of cytopathology is biopsy.

Cytopathology studies individual cells or small clusters of cells, not intact tissue. Its branches are named by how the cells are collected: exfoliative cytology uses cells shed naturally into fluids such as urine or sputum, abrasive cytology uses cells scraped or brushed from a surface, as in a Pap smear, and FNAC (fine needle aspiration cytology) draws cells out of a lump through a thin needle.

A biopsy removes a piece of tissue with its architecture intact, which is then processed and sectioned. That is the material of histopathology, not cytopathology.

Answer: B

The blanks are filled by Structural changes, diseases: histopathology deals with the structural changes brought about in the human body by diseases.

Histopathology examines tissue sections under the microscope to see how disease alters the structure of cells and tissues, such as inflammation, necrosis or tumour growth, and uses those changes to identify the cause.

Behavioural and personality changes belong to psychology and psychiatry. 'Clinical changes' are signs and symptoms seen at the bedside. The second blank also fails in those options: tissue, microorganisms or cells are not what brings about the changes the science studies; disease is.

Answer: D

The property an ideal fixative does not have is providing hyper-osmotic conditions to the tissues.

A fixative should preserve cells as close as possible to their living state. A hyperosmotic solution draws water out of cells and shrinks them, distorting the morphology the pathologist needs to see, so a good fixative is roughly isotonic.

The other three are genuine qualities of an ideal fixative: it should penetrate tissues and cells rapidly and evenly, it should not make the tissue excessively hard to cut, and it should be cheap and easily available. Formalin is widely used precisely because it meets these well.

Answer: A

Lymphocytes in the CSF point to viral meningitis.

Normal cerebrospinal fluid holds very few cells. In viral meningitis the cell count rises moderately and the cells are mainly lymphocytes, with normal glucose and a mildly raised protein. Bacterial meningitis, by contrast, gives a high count of neutrophils with low glucose. Tuberculous and fungal meningitis also give a lymphocytic picture, but neither is among the options.

Dehydration, chronic kidney disease and liver dysfunction do not cause inflammation of the meninges, so they do not raise the CSF lymphocyte count.

Answer: B

The sample for a platelet count is EDTA or double oxalated blood.

Platelets clump and stick to surfaces quickly, so the blood must be anticoagulated in a way that keeps them separate. EDTA chelates calcium and preserves platelet numbers and shape well, which is why it is the standard tube for blood counts; double oxalate is the older alternative.

An isotonic solution is a diluent, not a blood sample. A capillary sample may clot and give falsely low counts unless it is handled quickly. 'Anticoagulant added blood' is too vague: heparin, for example, causes platelet clumping, so the specific anticoagulant matters.