Page 292 - Textbook of Pathology, 6th Edition

276 24-hour collections of urine are useless for cytodiagnostic
purposes.
9. EFFUSIONS. Pericardial, pleural and peritoneal fluids
are obtained by paracentesis. As these fluids are often
exudative in character, they may clot after removal from
respective cavities. Anticoagulants may be used to prevent
coagulation—heparin (3-5 units per ml), 3.8% sodium citrate
(1 ml per 10 ml), or EDTA (1 mg per ml) may be used for this
purpose.
SECTION I
If the fluids cannot be processed within 12 hours of
collection, an equal volume of 50% ethanol or 10% formalin
should be added.

10. CEREBROSPINAL FLUID (CSF). CSF samples should
be despatched without delay to the laboratory for immediate
processing as the cells contained are extremely fragile. A gap
of even 1 hour between removal and processing may result
in loss of diagnostic cellular material.
11. SEMEN. Samples of seminal fluid obtained by
masturbation are best collected at the laboratory. Samples
obtained by coitus interruptus are collected in clean, dry test
Figure 11.9 Method of obtaining cervical smear with Ayre spatula tubes (or vials) and transported to the laboratory within 30
(fast smear). minutes. The patient is instructed to note the time of
ejaculation.

clean, dry, wide-mouthed glass container or a petridish. Care B. Fixation and Fixatives
should be taken to avoid spitting into the container. The
container is capped or covered, labelled and transported to All material for cytological examination must be properly
the laboratory where smears are prepared. fixed to ensure preservation of cytomorphological details.
Methods of fixation vary depending upon the type of staining
5. BRONCHIAL MATERIALS. All aspirated bronchial employed:
General Pathology and Basic Techniques
secretions, lavage, washings and brushings must be
Material for exfoliative cytodiagnosis is usually wet-fixed
despatched to the laboratory without delay. If immediate i.e. smears are immersed in fixative without allowing them
despatch is not possible, the sample should be collected in to dry. These smears are then stained with Papanicolaou
fixative (50% ethanol in volumes equal to that of the sample).
(Pap) or haematoxylin and eosin (H & E) stains.
6. BUCCAL SMEARS. The mouth is rinsed with water or Sometimes, exfoliative cytology smears are air-dried for
normal saline and the buccal mucosa scraped vigorously with use with the Romanowsky stains as are used in haematologic
a wooden or metal tongue depressor. The material is smeared studies. In Romanowsky staining, fixation is effected during
directly onto labelled glass slides which are placed in fixative. the staining procedure.
7. G.I. CYTOLOGY. In a case of suspected malignancy or 1. ROUTINE FIXATIVES. The ideal fixative for routine use
specific infections of GI tract, or for screening for Barrett’s is Papanicolaou’s fixative comprising a solution of equal parts
oesophagus, cytologic examination is indicated. The cytology of ether and 95% ethanol. However, the flammability of ether
specimen is collected during fibreoptic endoscopy of the part makes it hazardous. Most laboratories use 95% ethanol alone
being visualised. with excellent results. Where ethanol is not available, 100%
methanol, 95% denatured alcohol, or 85% isopropyl alcohol
8. URINE. Fresh catheterised specimens are preferred in (isopropanolol) may be used.
female patients while voided urine is satisfactory in males. Smears prepared at the bedside as well as those prepared
After initial morning voiding (which is discarded),
samples of about 50 to 100 ml are collected on three in the laboratory from fluid samples are immediately placed
consecutive days. Hydration by forced intake of fluids (1 glass in 95% ethanol without allowing them to dry prior to fixation.
Drying causes distortion of cells and induces cytoplasmic
of water every 30 minutes over 3 hour period) is recom- staining artefacts. Fixation time of 10 to 15 minutes at room
mended by some workers for production of high volume temperature is adequate. Smears may also be left in the
specimens. If delay is anticipated in despatch to the fixative for 24 hours or more without any detrimental effect
laboratory, the sample should be collected in an equal volume as regards cytomorphological detail. Smears should be
of 50% ethanol. transported to the laboratory in the fixative; screw-capped
The initial morning specimen is discarded as cells
deteriorate extremely quickly in acidic urine, and the Coplin jars are best for this purpose.
morphology of cells accumulating overnight in bladder urine 2. COATING FIXATIVES. Coating fixatives are applied as
is distorted to an extreme degree. For the same reason, aerosol-sprays or with a dropper to the surface of freshly