Order of drawing blood in vacutainers should be in the following sequence to prevent contamination?
All of the following are tests done for Turner mosaic screening except?
A 14 year old male presents with mushroom like tumor in the distal femur for past 2 years. Which of the following features suggest malignant transformation?
Abnormal accumulation of misfolded protein is seen in?
INI-CET 2023 - Pathology INI-CET Practice Questions and MCQs
Question 11: Order of drawing blood in vacutainers should be in the following sequence to prevent contamination?
- A. Grey, Blue, Red, Violet
- B. Blue, Red, Violet, Grey (Correct Answer)
- C. Blue, Violet, Red, Grey
- D. Red, Blue, Violet, Grey
Explanation: ***Blue, Red, Violet, Grey*** - This sequence follows the **CLSI (Clinical and Laboratory Standards Institute) order of draw** guidelines, which are critical for preventing **cross-contamination** between additives of different vacutainers. - The order starts with tubes for **coagulation studies** (blue top with sodium citrate), followed by serum tubes (red top), EDTA tubes (violet top for hematology), and finally glycolytic inhibitor tubes (grey top for glucose). - This prevents tissue thromboplastin contamination and anticoagulant carryover that could affect laboratory test results. *Grey, Blue, Red, Violet* - This order is incorrect as it places the **grey top tube** (containing fluoride/oxalate) first, which could contaminate subsequent tubes with its additives and affect tests. - The **blue top tube** for coagulation studies should come early in the sequence to minimize tissue thromboplastin contamination. *Blue, Violet, Red, Grey* - This sequence is incorrect because the **violet top tube** (EDTA) is placed before the **red top tube** (serum). - **EDTA contamination** can chelate calcium and other cations, interfering with chemistry tests performed on serum in the red top tube. *Red, Blue, Violet, Grey* - This order is incorrect as the **red top tube** is placed first, followed by the **blue top tube** (citrate). - The blue top tube should precede tubes with clot activators to **prevent tissue thromboplastin** from contaminating coagulation samples, which would lead to falsely shortened clotting times.
Question 12: All of the following are tests done for Turner mosaic screening except?
- A. Karyotype
- B. FISH
- C. Serum FSH (Correct Answer)
- D. Buccal smear
Explanation: ***Serum FSH*** - **Serum Follicle-Stimulating Hormone (FSH)** levels are used to assess ovarian function and can be elevated in conditions like Turner syndrome due to **gonadal dysgenesis**, but it is a **functional test**, not a screening tool for mosaicism. - While elevated FSH is a clinical feature of Turner syndrome, it does not directly screen for the chromosomal mosaicism itself. *Karyotype* - **Karyotyping** is the **gold standard** for diagnosing Turner syndrome and its mosaics by visualizing the entire set of chromosomes [1]. - It can identify various forms of mosaicism involving the X chromosome, where some cells have 45,XO and others have 46,XX or other variations [1]. *FISH* - **Fluorescence in situ hybridization (FISH)** is a molecular cytogenetic technique used to detect specific chromosomal abnormalities, including those associated with Turner mosaicism. - It uses DNA probes that bind to specific regions of the X chromosome, allowing for the rapid detection of **aneuploidy** or deletions that might indicate mosaicism [2]. *Buccal smear* - A **buccal smear**, historically used for **Barr body** analysis, can provide an initial screening for X chromosome abnormalities. - The presence of Barr bodies (inactive X chromosomes) can help differentiate between 45,XO (no Barr body) and mosaic variants like 45,XO/46,XX (variable number of Barr bodies). **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. (Basic Pathology) introduces the student to key general principles of pathology, both as a medical science and as a clinical activity with a vital role in patient care. Part 2 (Disease Mechanisms) provides fundamental knowledge about the cellular and molecular processes involved in diseases, providing the rationale for their treatment. Part 3 (Systematic Pathology) deals in detail with specific diseases, with emphasis on the clinically important aspects., pp. 54-55. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Genetic Disorders, pp. 186-187.
Question 13: A 14 year old male presents with mushroom like tumor in the distal femur for past 2 years. Which of the following features suggest malignant transformation?
- A. Cartilage thickness $>2 \mathrm{~cm}$ (Correct Answer)
- B. Presence of cartilage cap
- C. Location in metaphysis
- D. Size less than 1 cm
Explanation: ***Cartilage thickness >2 cm*** - A **cartilage cap thickness greater than 2 cm** in an osteochondroma in an adult (or >3 cm in children) is a strong indicator of **malignant transformation** into a secondary peripheral **chondrosarcoma**. [2], [3] - **Key imaging finding:** Cartilage cap measured on MRI or CT scan - Other features suggesting malignant transformation include continued growth after skeletal maturity, new or increasing pain, cortical destruction, and new soft tissue mass. [2], [3] *Presence of cartilage cap* - All osteochondromas have a cartilage cap by definition - this is a normal feature, not a sign of malignancy. [1] - The **thickness** of the cap, not its presence, is what matters. *Location in metaphysis* - Osteochondromas typically arise from the metaphysis near the growth plate - this is a normal location. [3] - Location alone does not indicate malignant transformation. *Size less than 1 cm* - Small size suggests a benign, stable lesion. - Malignant transformation is suggested by **increasing size** and growth after skeletal maturity, not small size. [2] **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, p. 1202. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Osteoarticular And Connective Tissue Disease, pp. 672-673. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, pp. 1202-1204.
Question 14: Abnormal accumulation of misfolded protein is seen in?
- A. Nephritic syndrome
- B. Sickle cell anemia
- C. Megaloblastic anemia
- D. Creutzfeldt-Jakob disease (Correct Answer)
Explanation: ***Creutzfeldt-Jakob disease*** - This is a neurodegenerative disease characterized by the accumulation of **abnormally folded prion proteins (PrPSc)** in the brain, leading to spongiform encephalopathy [1]. - The misfolding of normal cellular prion protein (PrPC) into its infectious and pathogenic form is central to the disease's pathology [2]. *Nephritic syndrome* - This syndrome is characterized by inflammation of the **glomeruli** in the kidneys, leading to hematuria, proteinuria, and hypertension. - It involves immune complex deposition and inflammation, not primarily the accumulation of misfolded proteins. *Sickle cell anemia* - This is a **genetic blood disorder** caused by a mutation in the beta-globin gene, leading to abnormal **hemoglobin S**. - While hemoglobin S can polymerize and deform red blood cells, it is not considered a disease of generalized misfolded protein accumulation in the same sense as prion diseases. *Megaloblastic anemia* - This condition is caused by impaired **DNA synthesis**, often due to **vitamin B12 or folate deficiency**, leading to large, immature red blood cells. - The pathology involves defective cell division and maturation, not the accumulation of misfolded proteins. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Central Nervous System, pp. 1284-1286. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Manifestations Of Central And Peripheral Nervous System Disease, pp. 712-713.