Do you heat fix a bacterial smear?

Do you heat fix a bacterial smear?

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. Allow the smear to air dry.

Why do we heat fix the slide before making a bacterial smear?

ost bacteria have no color, so they generate little contrast in the microscope field. First, bacteria are placed on a glass slide and “fixed” with heat, partly to ensure that they remain attached to the glass. Then, for simple staining, a basic stain is applied. Such a stain carries a positive electrical charge.

Why do you have to do heat fix before doing simple staining?

Heat-fix the dry smear by running the slide quickly through the flame a few times. The heat-fixing will coagulate some of the protein material and cause the suspension to adhere to the glass slide. A different dye will be used for each bacterium.

How do you heat fix a bacterial smear?

In order to heat fix a bacterial smear, it is necessary to first let the bacterial sample air dry. Then either place the slide in the slide holder of a microincinerator, or pass the dried slide through the flame of a Bunsen burner 3 or 4 times, smear side facing up. Once the slide is heat fixed, it can then be stained.

What does heat fixation do to a bacterial smear?

Heat fixation ensures the elimination of contaminating organisms from the smear preparation. Heat fixation adheres the cells to the slide and coagulates the bacterial proteins, effectively killing the bacteria.

What is the staining time during preparation of a blood smear?

Place slides into the working Giemsa stain (2.5%) for 45-60 minutes. Remove thin smear slides and rinse by dipping 3-4 times in the Giemsa buffer. Thick smears should be left in buffer for 5 minutes. Dry the slides upright in a rack.

Do you heat fix blood smears?

Protect thick smears from hot environments to prevent heat-fixing the smear. Do not fix thick smears with methanol or heat. If there will be a delay in staining smears, dip the thick smear briefly in water to hemolyse the RBCs.

What would happen if you heat fixed the smear before you air dry it?

Be patient and take the time to let your slide air dry before proceeding with adhering it to the slide. If your slide is wet and you heat fix it, the bacteria will boil and the cellular morphology will be lost.

What is smear give method for bacterial smear preparation?

Smear preparation technique consists of spreading small volume of sample on a slide and air drying the film before staining and microscopy. Bacterial smears must be prepared prior to any of the staining techniques.

In order to heat fix a bacterial smear, it is necessary to first let the bacterial sample air dry. Then either place the slide in the slide holder of a microincinerator, or pass the dried slide through the flame of a Bunsen burner 3 or 4 times, smear side facing up.

How do you fix a bacterial smear on a slide?

After heat fixing, touch the heated portion of the slide to your hand. It should be comfortably warm, but not burning hot. Take care not to under-fix (the smear will wash off) or over-heat (the cells will be ruptured or distorted) the slide. The correct amount of heat fixing is learned by experience. Allow the smear to cool and apply the stain.

How do you make a dried blood sample?

The technique for making and storing dried blood samples is given in the section “Dried Blood Samples”. Making a smear 1. A single smear can be made per slide (smear running the length of the slide) or two (or even three) smears can share a slide, with the smears running the width of the slide.

What’s the best way to prepare a bacterial smear?

First, use a wax pencil to draw a circle on the microscope slide to separate each type of bacteria that is going to be sampled. If a simple stain of only one type of bacteria, or single mixed sample of bacteria is being prepared, no separation is required.