Non-gynecologic cytology preparation

5 DOH Abu Dhabi (HAAD) lab licensing practice questions on Non-gynecologic cytology preparation, part of Histopathology and Cytology. The first 5 are below; the first 5 with answers and explanations (tap Show answer after you have chosen), the rest in Learn with a free account.

1. Question 1 · Medium

   From a thyroid nodule aspirate, one smear is air-dried for a Romanowsky stain and the next is wet-fixed at once for the Pap stain. Why prepare both?

   1. ARomanowsky stains can only be read under polarized light
   2. BPap stain needs the air-dried smear to stay well attached
   3. CRomanowsky shows colloid and cytoplasm; Pap shows nuclear detail
   4. DRomanowsky smears keep better for later immunostaining

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   Answer: C · Romanowsky shows colloid and cytoplasm; Pap shows nuclear detail

   Air-dried Romanowsky smears (Diff-Quik or May-Grünwald-Giemsa) show cytoplasm, background material such as colloid and mucin, and cell size well, and they stain in minutes for adequacy checks. Wet-fixed Pap smears give the sharpest view of chromatin, nucleoli and nuclear membranes. The two methods complement each other. Smears for Pap staining must reach the fixative before any drying.

   • A: Romanowsky stains are read with ordinary bright-field light.
   • B: Pap smears must be wet-fixed, never air-dried first.
   • D: Later immunostaining is usually done on a cell block or needle rinse.

2. Question 2 · Easy

   A cytocentrifuge (cytospin) preparation is most useful for:

   1. ARemoving thick mucus from a sputum sample before smearing
   2. BMaking a paraffin block from fluid sediment
   3. CStaining cells without any fixation step
   4. DConcentrating cells from sparse fluids such as CSF

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   Answer: D · Concentrating cells from sparse fluids such as CSF

   A cytocentrifuge spins a small volume of fluid onto a defined area of a slide, while filter card absorbs the liquid. This concentrates the few cells in CSF, urine or other dilute fluids into a small spot that is quick to screen. Slides can be air-dried for a Romanowsky stain or wet-fixed for Pap staining. Very cellular or bloody fluids may need dilution first to avoid thick, overlapping cells.

   • A: Mucus in sputum is handled with a mucolytic or by blending.
   • B: A cell block is made from clotted or gelled sediment.
   • C: Cytospin slides still need fixation before Pap staining.

3. Question 3 · Hard

   A pleural fluid from a 62-year-old man contains atypical cells, and the pathologist requests immunostains. The first cell block fell apart during processing, leaving only scattered cells in the paraffin. Which preparation step would best prevent this?

   1. AFix the fluid in 95% ethanol and send the whole volume
   2. BSmear the pellet on charged slides and fix in ethanol
   3. CBind the pellet with plasma-thrombin or agar before fixing
   4. DFreeze the pellet and cut it in the cryostat

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   Answer: C · Bind the pellet with plasma-thrombin or agar before fixing

   A loose cell pellet breaks up in the processor, so it is first held together in a matrix: a clot made with plasma and thrombin, or a gel such as agar or a commercial equivalent. The button is then wrapped, fixed in formalin and processed like tissue. Sections from it can be used for immunostains and special stains alongside the smears. Formalin fixation also keeps the staining comparable with protocols validated on tissue.

   • A: Fixing the whole fluid does not stop a loose pellet breaking apart.
   • B: Smears are useful, but they are not a block and give no serial sections.
   • D: Frozen sections lose morphology and do not give a permanent block.

4. Question 4 · Easy

   Saccomanno fixative, used to collect sputum for cytology, contains ethanol and:

   1. APolyethylene glycol (Carbowax)
   2. BMercuric chloride
   3. CGlacial acetic acid
   4. DFormaldehyde

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   Answer: A · Polyethylene glycol (Carbowax)

   Saccomanno fluid is about 50% ethanol with 2% polyethylene glycol (Carbowax). The ethanol fixes the cells, and the polyethylene glycol coats them and reduces shrinkage. The sputum is homogenized in a blender, centrifuged, and smeared from the sediment, with blending done in a biological safety cabinet. Deep-cough, early-morning samples on several days give the best yield.

   • B: Mercuric chloride is used in some tissue fixatives, not in Saccomanno.
   • C: Acetic acid lyses red cells, as in Carnoy's, but is not in Saccomanno.
   • D: Formaldehyde is not part of Saccomanno fixative.

5. Question 5 · Medium

   A 68-year-old smoker with painless hematuria is asked for urine cytology. Why is a first-morning voided sample usually avoided?

   1. AMorning urine has too few cells to examine
   2. BCells degenerate after hours in the bladder
   3. COvernight urine is too dilute for a cytospin
   4. DBacteria in morning urine lyse the red cells

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   Answer: B · Cells degenerate after hours in the bladder

   Cells shed into urine that has sat in the bladder overnight are exposed to it for hours and degenerate, which makes them hard to assess. A fresh second-voided or random midmorning sample, ideally after good hydration, gives better-preserved cells. If processing is delayed, the sample is refrigerated or prefixed according to the laboratory's protocol. Bladder washings give more cells but need instrumentation.

   • A: Cell numbers are not the problem; their preservation is.
   • C: Overnight urine is usually more concentrated, not more dilute.
   • D: Bacterial growth is a delay problem, and red cell lysis is not the main concern.