What are wet fixed smears?

Smears are air-dried or wet-fixed. Routine wet fixation is either in 70–90% ethanol or using a commercial spray fixative. Carnoy's fixative has the advantage of lysing red blood cells. Glutaraldehyde and 10% buffered formalin should be available if tissue fragments for EM or for paraffin embedding are obtained.

What is wet fixation?

1 For wet fixation numerous fixatives are used in exfoliative cytology of which 95% ethyl alcohol is most commonly used one. 2 The commonly practiced method is to dip the freshly spread FNAC smear immediately in 95% ethanol. 3 Other methods of smear fixation includes spray fixatives.

What is dry smear?

A new dry smear-rehydration technic is described. Slides prepared in such a manner invariably contained greater numbers of cellular elements. This method greatly reduces the large "wash-off" loss observed by us (and others) when slides are prepared by wet fixation.

Which fixation method is used for Pap smears?

Various fixatives are used in exfoliative cytology. Out of which, 95% ethanol is the commonly used fixative. Hence, the conventional method for fixation of Pap smear is to fix the Pap smear immediately in 95% ethyl alcohol after preparing the smear.

Why do we air dry smear?

This is important to ensure that the bacterial culture is fixed to the slide for proper visualization. Because of this, it is important to air dry a bacterial smear before heat fixing to prevent the boiling of excess water. By completely letting the bacterial smear air dry, any excess water is removed.

Smear and Heat fix

Why it is necessary to rinse the smear excessively with water?

Wash/rinse to remove excess dye. Gram's iodine is placed on the bacterial smear slide for one minute. Iodine acts as a mordant, a substance that helps to fix the dye to the thick peptidoglycan cell wall of Gram-positive bacteria. Wash/rinse to remove excess iodine.

What is the purpose of fixing a smear mark all that apply?

So the correct is so all of these options are correct to kill the bacteria to kill the bacteria so they aren't harmed by the staining method or to kill the bacteria to make slides safer to handle, to attach the bacteria to slide to break down the cell wall in order to make the cells except stain and to cause the cell ...

What are the types of fixation?

Depending on your specimen, you can choose one of the three general types of fixation processes – heat fixation, perfusion fixation, and immersion fixation.

What is the purpose of a fixative?

Functions of Fixative

The primary function of fixatives is to prevent autolysis (enzymes attack) as well as putrefaction (bacterial attack) of tissues. Autolysis seems to be a frequent issue in enzyme-rich tissues, and rigorously autolyzed tissue does not get stained properly for microscop- ic examination.

What is a liquid based cytology test?

Liquid-based cytology (LBC) is a new method of preparing cervical samples for cytological examination. Unlike the conventional 'smear' preparation, it involves making a suspension of cells from the sample and this is used to produce a thin layer of cells on a slide.

What are the two types of smear preparation?

Four different types of smear preparation methods (conventional method, blood film method, drop and rest method, and water-wash method) were carried out according to the standard reference as described below.

What is crushed smear?

Crush smear cytology is a cheap, easy and rapidly performing technique. The diagnostic yield is very high when the technique is combined with histopathology. It may be used as a useful adjunct to conventional histopathology.

What does a smear test do?

Contents. Cervical screening (a smear test) checks the health of your cervix. The cervix is the opening to your womb from your vagina. It's not a test for cancer, it's a test to help prevent cancer.

What is fixation in cytology?

In the fields of histology, pathology, and cell biology, fixation is the preservation of biological tissues from decay due to autolysis or putrefaction. It terminates any ongoing biochemical reactions and may also increase the treated tissues' mechanical strength or stability.

What is cellular smear?

Smears obtained from small cell carcinomas are usually highly cellular and composed of solitary noncohesive cells and small loose cell groupings. Most single cells appear stripped of cytoplasm, especially in cellular smears.

Which is the most commonly used fixative?

Formalin is most commonly used fixative. It is cheap, penetrates rapidly and does not over- harden the tissues. The primary action of formalin is to form additive compounds with proteins without precipitation.

What is a fixative solution?

Fixative: A medium such as a solution or spray that preserves specimens of tissues or cells. Most biopsies and specimens removed at surgery are fixed in a solution such as formalin (dilute formaldehyde) before further processing takes place.

What are the two methods of fixation?

The fixation methods are classified into chemical fixation and physical fixation. The former method chemically fixes proteins, lipids, etc., by using chemicals and the latter method physically fixes water in cells or tissues by freezing them.

Why are bacterial smears fixed?

The preparation of a smear is required for many laboratory procedures, including the Gram-stain. The purpose of making a smear is to fix the bacteria onto the slide and to prevent the sample from being lost during a staining procedure.

What happens if you heat fix a wet smear?

If your slide is wet and you heat fix it, the bacteria will boil and the cellular morphology will be lost. If your slide is wet and fix it in methanol, it will most likely wash off the slide. Smears that are too thick will most likely wash off the slide regardless of the fixation method.

Why are smears heat fixed prior to staining?

Heat fixing kills the bacteria in the smear, firmly adheres the smear to the slide, and allows the sample to more readily take up stains.

What happens if smear is too thick?

If the smear is too thick, proper decolorizing will not be possible. If the smear is overheated during heat fixing, the cell walls will rupture. Concentration and freshness of reagents may affect the quality of the stain.

What is a good bacterial smear preparation?

The first step in most bacterial staining procedures is the preparation of a smear. In a smear preparation, cells from a culture are spread in a thin film over a small area of a microscope slide, dried, and then fixed to the slide by heating or other chemical fixatives.

What is the purpose of allowing the bacterial smear to dry once it has been placed onto the surface of the slide?

What is the purpose of allowing the bacterial smear to dry once it has been placed onto the surface of the slide? Drying helps remove excess water to ensure optimal heat fixation. Air-drying adheres the bacteria to the slide.