biology

Romanowsky stain

Romanowsky stain is a biology topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Romanowsky stain rather than just read about it. In short: Romanowsky staining is a prototypical staining technique that was the forerunner of several distinct but similar stains widely used in hematology (the study of blood) and cytopathology (the study of diseased cells). Romanowsky-type stains are used to differentiate cells for microscopic examination in pathological specimens, especially blood and bone marrow films, and to detect parasites such as malaria within the bl…

Key takeaways

Romanowsky stain belongs to biology; place it in that map before memorising details.
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Connect Romanowsky stain to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Romanowsky stain from memory before moving on to harder problems.

Reference excerpt

Romanowsky staining is a prototypical staining technique that was the forerunner of several distinct but similar stains widely used in hematology (the study of blood) and cytopathology (the study of diseased cells). Romanowsky-type stains are used to differentiate cells for microscopic examination in pathological specimens, especially blood and bone marrow films, and to detect parasites such as malaria within the blood. The staining technique is named after the Russian physician Dmitri Leonidovich Romanowsky (1861–1921), who was one of the first to recognize its potential for use as a blood stain. Stains that are related to or derived from the Romanowsky-type stains include Giemsa, Jenner, Wright, Field, May–Grünwald, Pappenheim and Leishman stains. They differ in protocols and additives and their names are often confused with one another in practice.

Mechanism The value of Romanowsky staining lies in its ability to produce a wide range of hues, allowing cellular components to be easily differentiated. This phenomenon is referred to as the Romanowsky effect, or more generally as metachromasia. Eosin part of the stain is responsible for pink-orange hue of erythrocytes and granules inside cytoplasms of eosinophilic leukocytes.

Romanowsky effect

In 1891 Romanowsky developed a stain using a mixture of eosin (typically eosin Y) and aged solutions of methylene blue that formed hues unattributable to the staining components alone: distinctive shades of purple in the chromatin of the cell nucleus and within granules in the cytoplasm of some leukocytes. This became known as the Romanowsky effect. Eosin and pure methylene blue alone (or in combination) do not produce the Romanowsky effect, and the active stains which produce the effect are now considered to be azure B and eosin.

Polychromed methylene blue Romanowsky-type stains can be made from either a combination of pure dyes, or from methylene blue that has been subject to oxidative demethylation, which results in the breakdown of methylene blue into multiple other stains, some of which are necessary to produce the Romanowsky effect. Methylene blue that has undergone this oxidative process is known as "polychromed methylene blue". Polychromed methylene blue may contain up to 11 dyes, including methylene blue, azure A, azure B, azure C, thionine, methylene violet Bernthesen, methyl thionoline and thionoline. The exact composition of polychromed methylene blue depends on the method used, and even batches of the stain from the same manufacturer may vary in composition. Common method of rapid oxidation uses increasing pH of the solution with potassium carbonate and boiling it, which introduces atmospheric oxygen. Other methods have been employed, as well, such as oxidation in acidic medium with dichromate anion. Although azure B and eosin have been shown to be the required components to produce the Romanowsky effect, these stains in their pure forms have not always been used in the formulation of the staining solutions. The original sources of azure B (one of the oxidation products of methylene blue) were from polychromed methylene blue solutions, which were treated with oxidizing agents or allowed to naturally age in the case of Romanowsky. Ernst Malachowsky in 1891 was the first to purposely polychrome methylene blue for use in a Romanowsky-type stain.

Types

Wright stain

Wright's stain can be used alone or in combination with the Giemsa stain, which is known as the Wright-Giemsa stain. Wright's stain is named after James Homer Wright who in 1902 published a method using heat to produce polychromed methylene blue, which is combined with eosin Y. The polychromed methylene blue is combined with eosin and allowed to precipitate, forming an eosinate which is redissolved in methanol. The addition of Giemsa to Wright's stain increases the brightness of the "reddish-purple" color of the cytoplasmic granules. The Wright's and Wright-Giemsa stains are two of the Romanowsky-type stains in common use in the United States and are mainly used for the staining of blood and bone marrow films.

Jenner stain

Jenner's stain is used in microscopy for staining blood smears. The stain is dark blue and results in very observable clearly stained nucleus.

Giemsa stain

Giemsa stain is composed of "Azure II" and eosin Y with methanol and glycerol as the solvent. "Azure II" is thought to be a mixture of azure B (which Giemsa called "azure I") and methylene blue, although the exact composition of "azure I" is considered a trade secret. Comparable formulations using known dyes have been published and are commercially available. Giemsa stain is considered to be the standard stain for detection and identification of the malaria parasite.

May-Grünwald stain

The May-Grünwald-Giemsa is used for the staining of slides obtained by fine-needle aspiration in a histopathology lab for the diagnosis of tumorous cells.

Pappenheim stain

This method is a combination of May-Grünwald and Giemsa staining.

Leishman stain

In 1901 William Leishman developed a stain that was similar to Louis Jenner's but with the replacement of pure methylene blue with polychromed methylene blue. Leishman's stain is prepared from the eosinate of polychromed methylene blue and eosin Y using methanol as the solvent.

Field's stain

Field stain is used for staining thick blood films in order to discover malarial parasites.

Clinical importances

Blood and bone marrow pathology

Romanowsky-type stains are widely used in the examination of blood, in the form of blood films, and in the microscopic examination of bone marrow biopsies and aspirate smears. Examination of both blood and bone marrow can be of importance in the diagnosis of a variety of blood diseases. In the United States the Wright and Wright-Giemsa variants of the Romanowsky-type stains are widely used, while in Europe Giemsa stain is commonly employed.

Detection of malaria and other parasites Of the Romanowsky-type stains, the Giemsa stain is especially important in the detection and identification of malaria parasites in blood samples. Malaria antigen detection tests are an alternative to the staining and microscopic examination of blood films for the detection of malaria.

Use in cytopathology Romanowsky-type stains are also used for the staining of cytopathologic specimens such as those produced from fine-needle aspirates and cerebrospinal fluid from lumbar punctures.

History

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Illustrations

Romanowsky stain: Dmitri Leonidovich Romanowsky (1861-1921) — Dmitri Leonidovich Romanowsky (1861-1921)

Worked examples

Example 1 — a first encounter with Romanowsky stain

Start with the simplest possible case. Write down what Romanowsky stain claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Romanowsky stain before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Romanowsky stain ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Romanowsky stain

In research: Romanowsky stain appears in biology research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Romanowsky stain in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Romanowsky stain is common in secondary-school and first-year university syllabi. It links to neighbouring topics Anatomical pathology, Cytopathology, Eponyms in medicine, so understanding it makes those chapters shorter.
In everyday life: Look for Romanowsky stain outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Romanowsky stain in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Romanowsky stain means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Romanowsky stain out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Romanowsky stain in simple terms?

Why does Romanowsky stain matter?

Because it connects several biology ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Romanowsky stain?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Romanowsky stain.