Cytological smears within the scope of gynaecological cancer screening

Dr. Jacques Jenny, Zürich

Thanks to gynaecological cancer screening by means of colposcopy between 1940 and 1960 and cytological analyses which quickly gained popularity starting in 1960, cervical cancer has become the rarest form of genital cancer.

The purpose is to detect malignant alterations before they become invasive and can be cured with certainty by means of a relatively nonintrusive procedure. What has been done to date was a success. Nevertheless, we are aware of the fact that screening does not offer complete protection. It happens from time to time that a malignant lesion is diagnosed in an examination performed in the aftermath of negative findings.

It is presumed that approximately two thirds of all false-negative results are due to the inadequate collection of the smear by the physician and only a third due to screening or interpretation errors at the lab.

Based on our experience, a lack of cells, inflammation, cell degradation, masking of diagnostic cells due to the overlap and absence of endocervical cells in the smear are the most common causes for suboptimal material.

Cytologists can only establish the diagnosis for malignancy or their exclusion with relevant specimens which must contain:

  • a sufficient amount of
  • well preserved
  • well visible cells.

In addition, it has to be made sure that the entire area in which pathological alterations can develop has been covered by the smear. The specimen must contain:

  • squamous epithelial cells from the ectocervix
  • columnar epithelial cells from the endocervix and the ectopy and/or
  • cells from the cervical transformation zone.

A single cell with atypical appearance is not sufficient to establish the diagnosis for malignancy; the diagnosis for malignancy or its exclusion can only be established using well preserved, well defined cells with intact cytoplasm.

Adequate quantity or representative cells

The quantity of diagnostic cells in the smear depends on:

  • the location
  • the planar extent of the lesion
  • the type or condition of the epithelium, but in particular on the smear collection technique and
  • the instruments used for it.

Direct smear collection method

Direct smear:
The quantity of diagnostic cells is greatest if the smear is taken directly from the surface of the lesion. 

It decreases rapidly as soon as the direct collection is no longer ensured, because in this case only spontaneously desquamated cells are harvested which found their way from the location of the lesion to the specimen collection site. Their number is all the lower the greater the distance is between the lesion and the withdrawal site. 

The longer the distance a cell has covered from the location of the lesion to the withdrawal site, i.e. the longer it was in a foreign milieu separated from the tissue conglomerate, the greater the secondary degenerative alterations will be.

Fig.1: Quantity of pathological cells in the smear depending on the location of the lesion.

The quantity of diagnostic cells in the smear increases with the planar extent of the lesion which has a direct correlation with its degree of severity.

Fig. 2: Quantity of pathological cells in the smear depending on the location of the lesion.

Alterations on the surface of the portio are directly visible with the eye and on a smear (region containing squamous epithelial cells 1 transformation zone 1 ectopy). It is easy to harvest plenty of cellular material. 

However, the collection from the cervical canal is more difficult. The expected quantity of material harvested from lesions located inside the cervix is all the lower the higher up the alteration is located in the cervical canal and is unreachable with the specimen collection. 

Cells from alterations of the endometrium are only infrequently found in routine smears. 

Cells from alterations of the tubes or even the ovaries occur only very rarely in the smear. The results of early cytological screening are accordingly (Figure 3).

Distance from the lesion to the colletion siteOvaryTubenCavumCervical canalPortioVulva
Desquamation tendency+/-+/-+/-+/-++++/-
Quantity of cells in the smear00+/-++++++/-
Expected cytological result00+/-++++++/-
Routine diagnostic possibilities
Speculum examination000+/-0+/-
Bimanual examination++0000
Other work-up procedures
Biopsy -*) Streak curettage000++*)++++++
Curettage / aspiration00+++++*)00
Laparoscopy / laparotomy++++++0000

Type and condition of the epithelial tissue (Figures 4A - C) 

The squamous epithelium lines the vaginal walls and the surface of the portio; it has a good and constant desquamation tendency. Accordingly, the smear mainly contains a large quantity of squamous epithelial cells – numbering in the hundreds of thousands.  

Their number decreases under the effects of oestrogen (middle of the cycle). They are isolated and spread out evenly. 

The smears contain more cells under the effects of gestagen (advanced secretion phase, pregnancy). The cells are folded and densely abutted on one another. With absent effects of sex hormones (atrophy), the smears often contain few cells. 

In contrast, the endocervical columnar epithelium only desquamates a small number of cells. Endocervical cells are often found in the cervical mucus. Because of their low resistance to exterior influences, they are affected by degenerative alterations. Their appearance is multifaceted.


Fig. 4: Quantity of cells in the smear: A) in the late proliferation phase, B) in the advanced secretion phase or pregnancy, C) in the presence of atrophy, D) columnar epithelium of the endocervix. 

Normal epithelium is characterised by good cellular cohesion – it is flexible and deforms on contact with an object scraping it. The quantity of spontaneously desquamated cells varies depending on the hormonal status. The cells harvested with direct collection are desquamated cells or cells in the process of separating from the epithelial conglomerate. (Figure 5) 

The cellular cohesion is reduced in epithelium with pathological alterations. A significantly greater number of cells are desquamated than in healthy epithelium. If a firm object is scraped across it, the number of cells separated from the epithelial conglomerate is give or take plentiful and with invasive cancer it even penetrates the tissue (Chrobak probe test). This is the reason why a disproportionately greater quantity of cells can be harvested with the direct collection from relatively small areas with neoplastic alterations than from surrounding healthy tissue. (Figure 6 and 7B) 

Reduced cellular cohesion not only occurs in the presence of neoplastic alterations. The quantity of cells in the smear is also increased greatly in the presence of inflammation. In addition, the smear contains plenty of granulocytes and often erythrocytes as a result of increased damageability of the epithelium.(Figure 7A)


Fig. 5: Healthy epithelium with good cellular cohesion. The tissue is flexible and gives way when a solid object is used to scrape it. The quantity of cells in the smear varies depending on the hormonal condition.

Fig. 6: Neoplastic epithelium with reduced cellular cohesion. A solid object is capable of separating cells from the epithelial conglomerate. The relative number of neoplastic cells is high.

Fig. 7: Quantity of cells in the smear in the presence of: A) inflammation, B) malignant neoplasia.

The relative number of pathological cells (Figure 8) is highest if the smear is taken in the late proliferation phase or in the presence of inflammation. It decreases with increasing effect of gestagen (advanced second phase of the cycle, pregnancy). The best time to take a smear is at the time of ovulation (important for repeat smears).

Fig. 8: Relative number of diagnostic cells in the smear when the smear is taken A) in the advanced proliferation phase,  B) in the advanced secretion phase, C) in the presence of inflammation from an area of neoplastic cells with identical size and type.

Smear collection technique and instruments

The smear should be taken with an instrument that allows harvesting a sufficient quantity
of diagnostic cells (Figures 8a + 8b).  

Collection with a cotton swab: If a cotton swab is used to collect the specimen, only desquamated cells or cells in the process of separating from the epithelial conglomerate will be wiped off. In addition, a large quantity of cells remains trapped on the cotton and is not transferred onto the microscope slide, i.e. the loss of material is high. The number of cells in the smear is often low and the conservation status of the cells inadequate.  

Collection with a spatula: If the material is harvested directly from the location of the lesion using a solid object, i.e. a spatula and with the application of light force, vital cells can always be harvested from the epithelial conglomerate. The advantage is that the cellular cohesion within a neoplastic alteration is lower than in regular tissue. A disproportionately greater quantity of atypical cells can be harvested from a small neoplastic area than from surrounding healthy epithelium. The relative number of pathological cells will be high. The quantity of atypical cells in the smear grows with the planar extent of the lesion which has a direct correlation to its degree of severity. It is expected that the quantity of diagnostic cells increases with the severity of the lesion.

We were able to demonstrate with 300 swab smears taken simultaneously with both methods, that smears taken with a spatula contained more and better preserved cells. The spatula collection is significantly superior to the cotton swab collection.  

The light application of force when taking the smear should not be underestimated for the identification of neoplastic alterations. This is particularly true for neoplasias with a tendency to keratinize at the surface, because the keratinized layer prevents the exfoliation of tumour cells from the depth. (Figures 9 and 10)This disadvantage can only be overcome with the Cyto spatula. 

Moreover, the superficial layers of invasive carcinomas are often necrotic and covered with inflammatory elements and therefore, well preserved diagnostic tumour cells can only be harvested when the smear is taken with the application of some force. (Figure 11)

The admixture of fresh blood does not interfere with the evaluation of the smear, so long as the specimen was collected properly and a thin and uniform layer is spread onto the slide.

Fig. 10: Smear taken with a cotton swab compared to a smear taken with a spatula for keratinizing invasive squamous cell carcinoma.

Fig. 11: Smear collection using a cotton swab compared to the smear collection using a spatula for invasive squamous cell carcinoma with necrotic and inflammatory alterations of the surface.

The purpose of the smear collection is to harvest as many diagnostic cells as possible from a potentially present lesion.  

The epithelial surface of the vagina and portio from which squamous epithelial cells are desquamated into the vaginal secretion is many times larger than the planar extent of a neoplastic alteration. Although a significantly greater quantity of cells is desquamated from a neoplastic area compared to healthy tissue, the relative number of diagnostic cells is expected to be fairly low. (Table 1)

Normally, the desquamated cells are eliminated by the self-cleaning of the vagina and the vaginal secretion is not increased. With the pronounced effects of gestagen and especially in the presence of inflammation, the vaginal secretion is increased and covers the vaginal walls and the surface of the portio. The smears contain a markedly high number of cells. They contain large quantities of non-diagnostic elements and only very few diagnostic cells (Figures 12A and 12B).

This error can easily be eliminated by carefully removing the large quantity of vaginal secretion from the surface of the portio with a swab prior to taking the smear.


Collection instrument:Cotton swabSpatula
+vaginal secretioncleaned+vaginal secretioncleaned
Normal cells+++++++++++++++
Atypical cells+++++++
Relative number of atypical cellsvery lowlow0+/-

Table1: quantity of normal and atypical cells harvested with smears taken from the portio covered with vaginal secretion and from the portio cleaned from vaginal secretion using a cotton swab and a spatula.  

Fig. 12: Quantity of diagnostic cells in the smear taken with a cotton swab and with a spatula before the removal of increased vaginal secretion from the surface of the portio.

Fig. 13: Relative number of diagnostic cells in the smear taken with a cotton swab and a spatula after the removal of increased vaginal secretion from the surface of the portio.

Loss of cells associated with the preparation

The smear contains hundreds of thousands of normal squamous epithelial cells, a more or less large quantity of endocervical cells and metaplastic cells, transudate, cervical mucus, leukocytes and possibly blood. The quantity of atypical cells is usually significantly lower.

Because only approximately 10 to 20% of the material is transferred onto the microscope slide, it is possible that the slide contains only very few or no diagnostic cells at all. This is more likely the lower the number of diagnostic cells was in the original material.

The absence or insufficient quantity of diagnostic cells in a false-negative smear can have two reasons:

  1. a collection error in the narrow sense, i.e. the relevant region was missed when the smear was taken;
  2. preparation error: although diagnostic cells were harvested when the specimen was collected, only a very small quantity or none at all were transferred onto the microscope slide.

Therefore, it is essential that as many cells as possible are harvested from a potentially present lesion during the collection and that the entire instrument is carefully spread across the entire surface of the microscope slide.  

To harvest a sufficient quantity of diagnostic cells, the following must apply:

  1. the direct collection principle must be ensured
  2. an instrument must be used which allows the specimen collection with the application of some force
  3. the surface of the portio must be cleaned from vaginal secretion before taking the smear.

The smear must be taken from the correct location

(Dr. Jacques Jenny, Zurich) 

Approximately 30% to at most 35% of all cervical intraepithelial neoplasias and cancers of the portio develop in the original squamous epithelial region, 50 to 55% within the ectopy and transformation zone and 10 to 15% in the endocervix.

Fig. 14: Location of cervical intraepithelial neoplasias and cancers of the portio. 

The smear is only relevant if it covers the entire area in which neoplasias develop, i.e. not only the entire surface of the portio, but also the cervical canal.

A relevant smear must contain:

  • original squamous epithelial cells
  • glandular cells from the endocervix and the ectopy and/or
  • cells from the transformation zone

The swab should be collected under visual control. The portio should be aligned with the pelvic axis, which is usually quite easy by tipping the speculum or with the use of a swab with a stem.

Cell material can easily be harvested from the surface of the portio with any instrument.  

A cotton swab is frequently still used for the specimen collection from the cervical canal which is often difficult to be inserted into the cervical canal and thus does not guarantee a direct collection.  

The SZALAY Cyto spatula matches the anatomical shape of the portio. It can also be inserted if the external os is narrow and allows the direct collection from both the surface of the portio as well as the cervical canal using a single instrument.  


The portio is adjusted with a speculum and aligned with the pelvic axis. The lean tip of the SZALAY Cyto spatula with a length ranging from 1.5 to 2.0 cm is inserted into the cervical canal as far as required for its shoulder to be completely abutted against the surface of the portio. The Cyto spatula is then rotated 360 degrees several times with the application of light force. If the os uteri is wide, the spatula should be guided in such a way that its tip remains in constant contact with the wall of the cervical canal.

Fig. 15: Taking the smear with the SZALAY Cyto spatula allows the direct collection from both the surface of the portio as well as the cervical canal.  Always use the largest of the three available models (small (no. 1), medium (no. 2), large (no. 2)) whose tip can still fit into the cervical canal.

Fig. 16: Sample material can easily be collected from the surface of the portio with a spatula, while it is often difficult to insert a cotton swab far enough into the cervical canal (direct collection is impossible).

The swab collection can induce minor seeping haemorrhage, which can easily be controlled with a silver nitrate infused swab.  


Examinations conducted at my practice have shown that it is impossible in 8.30% of women up to age 29 to insert the cotton swab into the cervical canal versus only 2.5% for the SZALAY plastic spatula; the corresponding number in women aged 30 to 39 is 8.0% versus 2.2% and 14.2 % versus 3.5% in women aged 40 to 49.

Cotton swab8.4%8.0%14.2%24.3%58.8%79.3%
Szalay Cyto-Spatula2.5%2.2%3.5%8.8%14.0%17.1%

Table 2: Incidence rate where it was impossible to insert the instrument (cotton swab or Szalay Cyto spatula) into the cervical canal by 10-year age groups. 

The quality of smear specimens has significantly improved since 1980 when the cotton swab was replaced by the Szalay spatula, yielding more consistent results on average. The number of smears with non-representative material has dropped from 0.7% to 0.30% and the number with material that is only representative to a limited extent  from 14.7 to 9.1%. 

The breakdown of the smear quality divided by gynaecologists and general practitioners showed that the quality of smears taken by specialists for gynaecology was not superior to the one of smears taken by general practitioners.

Specimen quality 1976-1980Gynaecologists [%]GPs [%]Total  [%]
Only representative to a limited context13.517.514.7
Specimen quality 1981-1994Gynaecologistst [%]GPs [%]Total  [%]
Only representative to a limited context8.511.39.1

Table 3: Specimen quality from 1976 - 1980 (279,414 smears) and from 1981-1995 (1,132,692 smears) itemised by gynaecologists and general practitioners. 

The smear quality varies depending on the collector. It ranges from optimal to non-representative material. Every collector has his own “personal style“.

Specimen quality 1981-1994Minimum [%]Maximum [%]Average [%]
Only representative to a limited extent20.51.58.5

Table 4: Differences in the quality of specimens submitted by 30 gynaecologists who are taking more than 100 smears per month.

An instrument should be used for the swab collection which allows the direct collection in a single work step from both the surface of the portio and the cervical canal.

Well preserved cells

To obtain well preserved cells, the swab collection should be carried out under suitable conditions.

a. Inflammation or atrophy 

In the presence of massive inflammation or atrophy associated with viscous vaginal content, the cells often have severe degenerative alterations, making it difficult to analyse them. Postpone the swab collection to a second consultation after treating the inflammation or after the build-up with local oestrogen application.

Conservation status of the cells
Vital cells are normally well preserved. The nucleus with its chromatin structure and the cytoplasm can be seen clearly.
Inflammation causes damage to the epithelium and cell degeneration. Unspecific alterations involving the cytoplasm and the nuclei occur in the process.
Regenerative reparative processes with increased biological activity are taking place simultaneously. Immature cells, equally showing unspecific alterations are determined in the smear.
As a result, the appearance of benign cells can almost be malignant while the malignancy criteria of neoplastic cells are almost blurred.
In extreme cases, the epithelial cells are covered with inflammatory elements to such an extent that they are almost no longer visible. This severely complicates the cytological analysis or even makes it impossible.
Squamous epithelial cells are relatively resistant against exterior influences. Their sensitivity is reciprocally proportional to their degree of differentiation. Usually, surface and intermediate cells are well preserved even in the presence of massive inflammation, while immature cells often show extensive degeneration phenomena. Remember: tumour cells are often undifferentiated cells which easily switch to degeneration.
The cell resistance of columnar epithelial cells is low. In the smear, they often show degenerative alterations, giving them a multifaceted appearance. Frequently, only bare nuclei can be found of them.

b. Tumour / ulcer

Cytology is the most universal and reliable method for the detection of preliminary and early stages of uterine cervix cancer. This does not apply to visible tumours or ulcers. Cytological results are inadequate due to inflammatory and necrotic alterations at the surface of the tumour. Detritus, fibrin, necrotic material, granulocytes and erythrocytes often dominate the appearance of the smear to such an extent that cells indicating malignancy are virtually unrecognisable. In the majority of cases, this relates to clinically manifest alterations visible with the naked eye or at least with colposcopy. The diagnosis must be clarified with a biopsy.

c. Smears taken during early puerperium

They are inappropriate with respect to cancer screening. In the absence of a special indication, the swab collection should be postponed until the menstruation resumes.

The swab should be taken under “suitable conditions”.

Well visible cells

The visibility of the cells depends on the conditions under which the smear was taken and to a large extent also on how the specimen material was spread onto the slide. 

Diagnostic cells are „masked“ by overlap and are barely recognisable. This risk is particularly present in cell-rich inflammatory smears containing plenty of granulocytes, fibrin, detritus, exudate and other interfering elements or in preparations in which the layer of specimen spread onto the slide is too thick. When spreading the specimen onto the microscope slide, place the spatula flat onto the slide and spread preferably one thin and even layer of cell material horizontally across the entire length of the slide with one or several strokes.
Wipe off any mucous streaks over the edge of the microscope slide.
Fresh blood does not interfere with the analysis so long as the specimen was collected and spread onto the slide properly.

A thin and even amount of the smear material taken from the tooth (cervical canal) and tongue (surface of the portio) is spread across the entire length of the microscope slide with several gentle strokes starting from the labelled side.

After spreading it onto the slide, the person collecting the sample should make sure that the microscope slide contains an adequate amount of material. If this is not the case, the spatula should be spread across the slide again or a second smear be taken.

The condition for relevant smears is that a thin and even layer of cell material is spread onto the slide and fixed immediately.

The cells shrink upon drying and their appearance changes. Therefore, the microscope slide must be immersed into a vessel for fixation immediately after the material has been spread on, and left in the fixation solution for at least 30 minutes. Several hours or even days of fixation do not impair the preparation.

If the vessel is always closed, the fixation solution can be used for several days.

Our preferred fixation solution is the DELAUNAY fixation solution:
-Abs. alcohol / acetone aa 500 mL,
-Trichloroacetic acid solution 1 mol 1 mL,
Alternatively, ethyl alcohol 96 percent may be used.
When using a fixative spray, please make sure that the spray is applied onto the preparation from the side at a distance of at least 15 cm.

In summary

The conventional swab collection is simple and definitely capable of supplying optimal material, provided the following conditions are met:

  1. The instrument used for the collection must allow the withdrawal with the application of some force both from the surface of the portio and the cervical canal (SZALAY Cyto spatula).
  2. The material should be collected directly from the location of the lesion (direct collection).
  3. The surface of the portio must be cleaned from excess vaginal secretion before taking the smear.
  4. The smear should be taken under adequate conditions.
  5. A thin and even amount of the specimen material should be spread across the entire microscope slide and fixed immediately.
  6. The contribution from the laboratory is to guarantee an optimal staining quality.


Dem Material für zytologische Untersuchungen muss ein in gut leserlicher Schrift (Schreibmaschine / Blockschrift) ausgefülltes Auftragsformular beiliegen.

Folgende Angaben müssen angegeben werden:

  • Name, Vorname, vollständiges Geburtsdatum
  • das Datum der Abstrichentnahme
  • das Datum der letzten Menses bzw. der Zeitpunkt der Menopause
  • die letzte zytologische Untersuchung mit der entsprechenden Protokoll-Nummer (Feld "letzter Abstrich").

Klinische Angaben sollen in den entsprechenden Feldern angekreuzt werden:

  • Blutungsstörungen
  • Fluor braun 1 blutig
  • Gravidität, Geburt in letzten 3 Monaten
  • Hormonbehandlung
  • vorausgegangene operative Eingriffe
  • vorausgegangene Strahlenbehandlung 1 Chemotherapie
  • Anlass für Abstrich: Vorsorge 1 Anamnese 1 Lokalbefund
  • Portio unauffällig 1 suspekt 1 Tumor (falls kolposkopiert wurde ist der Befund einzutragen).

Besondere klinische Symptome sollen angegeben werden.

Die Abstrichentnahme

  1. Das zur Entnahme benötigte Material (Entnahmespatel / Objektträger / Fixationslösung) wird in Reichweite des Untersuchers bereitgelegt.
  2. ldentifikation der Präparate: Um jede Verwechslung zu vermeiden werden Name und Jahrgang der Patientin erst unmittelbar vor der Abstrichentnahme auf das Mattschild des Objektträgers eingetragen. Da alle anderen Beschriftungen beim Färbevorgang verloren gehen ist dazu ist ein Bleistift zu gebrauchen. Nicht verwendete, beschriftete Objektträger sind wegzuwerfen. Nicht mit dem Namen der Patientin versehene Objektträger dürfen im Labor nicht verarbeitet werden.
  3. Die Portio wird mit trockenem Speculum eingestellt und in Führungslinie gebracht. Grössere Mengen von Vaginalsekret und Schleim, die die Portio bedecken werden mit einem Watteträger oder Gazetupfer schonend abgewischt.
  4. Vor der Abstrichentnahme soll eine massive Entzündung ausgeschlossen werden. Dies geschieht durch die Inspektion und/oder die Kolposkopie. Aufgrund der Untersuchung eines Nativpräparates unter dem Phasenkontrastmikroskop kann die Qualität des Vaginalsekrets beurteilt und entschieden werden ob es sinnvoll ist einen Abstrich zu entnehmen oder ob die Abstrichentnahme nicht auf eine zweite Sitzung - nach Sanierung der Lokalverhältnisse - verschoben werden soll. Durch den Erregernachweis gibt sie die notwendigen Hinweise auf die einzuschlagende Therapie. Sie eignet sich besonders gut für die tägliche Praxisroutine und lässt sich problemlos in den Ablauf der normalen gynäkologischen Untersuchung einbauen.
  5. Abstrichentnahme mit SZALAY Cyto-Spatula: Die schlanke 1,5 bis 2,0 cm lange Spitze des Spatels wird so hoch in den Zervikalkanal eingeführt bis die Schulter des Spatels der Portiooberfläche anliegt. Dann wird der Spatel, beginnend bei 6 Uhr , unter sanftem Druck mehrmals um seine Achse gedreht- Bei weitem Muttermund ist der Spatel so zu führen, dass seine Spitze stets in sattem Kontakt mit der Wand des Zervikalkanals bleibt.Bei der Entnahme ist darauf zu achten, dass das gesamte Drüsenfeld bis über den Rand der Umwandlungszone hinaus abgestrichen wird. Ist die Schulter des Spatels ausnahmsweise zu schmal (breite Ektopie) so muss das restliche Drüsenfeld mit einem gewöhnlichen Holzspatel auf einen zweiten Objektträger abgestrichen werden.
    Von den drei zur Verfügung stehenden Modellen wird immer der grösstmögliche verwendet dessen Zahn noch vollständig in den Zervikalkanal eingeführt werden kann.
    Die Patientin soll darüber aufgeklärt werden, dass es bei der Abstrichentnahme zu gering gradigen Sickerblutungen kommen kann. Sie lassen sich durch betupfen mit Silbernitrat leicht stillen.
  6. Ausstreichen des Materials auf Objektträger: Anschliessend wird das Material vom flach auf den Objektträger aufgelegten Spatel durch mehrere zarte Striche von der beschrifteten Seite her über die ganze Länge des Präparates dünn und gleichmässig ausgestrichen. Schleimschlieren müssen über die Kante des Objektträgers abgewischt werden.
    Frisches Blut stört die Beurteilung nicht sofern das Material dünn ausgestrichen ist. Nach dem Ausstreichen muss sich der Entnehmer vergewissern dass sich genügend Material auf dem Objektträger befindet. Ist dies nicht der Fäll, so soll der Spatel nochmals ausgestrichen oder ein zweiter Abstrich angefertigt werden.
  7. Der Plastikspatel wird nach Gebrauch weggeworfen.
  8. Fixation: Das Präparat wird sofort fixiert und muss mindestens eine halbe Stunde in der Fixationslösung belassen werden. Fixation von mehreren Stunden, ja Tagen schadet dem Präparat nicht. Sofern die Fixationslösung verschlossen gehalten wird kann sie mehrere Tage verwendet werden.
    Als Fixationsmittel bevorzugen wir die Fixationslösung nach DELAUNAY.

    - Alkohol abs. 1 Aceton aa 500 ml.
    - Acid. trichloracet. sol 1 mol. 1 ml.

    Es kann auch Aethylalkohol 70% bis 96% verwendet werden.
    Wir geben der Fixation im flüssigen Medium in einer Küvette den Vorzug. Wird trotzdem mit einem Spray fixiert, ist streng darauf zu achten, dass der Strahl, wie in der Beschreibung angegeben, aus einer Entfernung von mindestens 25 cm von der Seite her auf das Präparat aufgesprüht wird.
  9. Die Präparate werden, zusammen mit den Auftragsformularen, trocken in den vom Labor zur Verfügung gestellten Packungen eingeschickt.
    Falls Sie einen Fall histologisch abklären, bitten wir Sie uns eine Kopie des Histologieberichtes zukommen zu lassen. Für das zytologische Labor ist diese Information von grösster Bedeutung. Nur anhand der Korrelation zwischen zytologischer Diagnose und histologischem Befund kann die diagnostische Arbeit des Labors überprüft und die Qualität verbessert werden.

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