Giemsa stain - Principle, Composition, Procedure, Uses

Introduction to Giemsa stain

Giemsa stain is a nucleic acid stain that stains the nucleotides i.e. deoxyribonucleic acid (RNA) and ribonucleic acid (DNA). This stain is used in cytogenetics as well as for histopathological diagnosis of malaria as well as other parasites such as the trophozoite Trichomonas vaginalis.

In addition, Giemsa stain is also a differential stain. It can be combined with Wright stain to form Wright-Giemsa stain.

History of Giemsa stain

The Giemsa stain is named after its creator, Gustav Giemsa. Giemsa was a German chemist and bacteriologist.

Principle of Giemsa stain

Giemsa stain is specific to the phosphate groups present in the DNA. It adheres to the regions of DNA which have high amounts of adenine-thymine bonding.

Composition of Giemsa stain

Giemsa stain is composed of a mixture of methylene blue, eosin, and Azure B. This stain is available commercially.

Procedure for using Giemsa stain

Giemsa stain is used by following procedures:

1. make a thin film of the specimen on a microscope slide

2. fix the slide by immersing the slide in pure methanol for 30 seconds or by adding a few drops of methanol to it

3. the slide is then immersed in a freshly prepared 5% Giemsa stain solution for 20–30 minutes

   * in emergencies 5–10 minutes in 10% Giemsa stain solution can be used

4. gently wash the slide under slow-running water

5. air dry and view under a microscope

Uses of Giemsa stain

The significant uses of Giemsa stain are as follows:

Giemsa banding

The Giemsa stain is used in Giemsa banding, also known as G-banding. It stains the chromosomes and is used to create a chromosome map called a karyogram. This method can detect chromosomal anomalies including translocations and rearrangements.

As differential stain

When combined with Wright stain to form Wright-Giemsa stain, Giemsa stain can be used as a differential stain. Since it stains human cells purple and bacterial cells pink, the Wright-Giemsa stain is used to study the adherence of pathogenic bacteria and blood parasites (eg. Plasmodium spp., spirochete, protozoa) to human cells.

In blood film

Giemsa stain is used as a classic blood film stain. It is used mostly for bone marrow specimens and peripheral blood smears. It is also used to demonstrate the classic "safety pin" shape in Yersinia pestis. Different blood components stain differently under the Giemsa stain, which is listed below

• Erythrocytes = stain pink

• platelets = stain a light pale pink

• lymphocyte cytoplasm = stains sky blue

• monocyte cytoplasm = stains pale blue

• leukocyte nuclear chromatin = stains magenta

In virology

Giemsa stain is also used to demonstrate chromosomes during viral infection. One such example is for diagnosis of Cytomegalovirus infection, characterized by an "owl-eye" viral inclusion.

Others

Other important uses of Giemsa stain are during the diagnosis of dimorphic fungi Histoplama, intracellular sexually transmitted bacteria Chlamydia, and even mast cells.