There are two types of cervical cytology specimen type. Conventional cytology and liquid based cytology.
Gynecological cytology examinations can thus be performed conventionally (on a glass slide) or by the methods known as liquid-based (tube) cytology.
Conventional cytology is a technique used for more than 50 years in the prevention and early diagnosis of cervical cancer. The cytology in the liquid medium was introduced in the 90’s, as an alternative method, aiming at the automation in the preparation of the harvested material and proposing improvements for the professional and patients at the moment of the glass slide observation (Heise, A. & Lima, A.P.W., 2016).
Conventional cytology samples are obtained using a spatula or “brush” to obtain cells from the cervix so they can be spread on the slide, fixed and then observed under a microscope (Figure C4).
Figure C4. Conventional cytology.
For the collection of cytology in liquid medium, the sample is transferred to a liquid medium in order to better preserve the cells, DNA, RNA and proteins. The sample is further processed so that the cells are arranged in a thin layer without artifacts and without overlap (monolayer) (Figures C5 and C6).
Figure C5. Examples of liquid based cytology tubes.
Figure C6. Liquid based cytology slide.
According to Campagnoli et al. (2011), the advantages of cytology in liquid medium compared to conventional cytology are:
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- simplification of the sampling technique
- decrease in cellular artifacts leading to fewer inadequate diagnoses
- applicability of additional investigations / techniques
The main disadvantage is the high cost.
References:
Campagnoli E. B. et al., 2011. Comparação entre a citologia em base líquida e a citologia esfoliativa convencional no diagnóstico de carcinomas da região de cabeça e pescoço. Pesq Bras Odontoped Clin Integr, v. 11, n. 1, p. 65-71.
Heise, A. & Lima, A.P.W., 2016. Citopatologia convencional e citologia em meio líquido: uma revisão integrativa. Revista Saúde e Desenvolvimento, 10(5), pp.208–221.
