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Introduction of Tzanck smear

Tzanck test is named after Arnault Tzanck (1886–1954), a French dermatologist. Tzanck test, also Tzanck smear, is scraping of an ulcer base to look for Tzanck cells. It is sometimes also called the chickenpox skin test and the herpes skin test. Tzanck cells are multinucleated giant cells. They are  found in:

1. Herpes simplex
2. Varicella and herpes zoster
3. Pemphigus Vulgaris
4. Cytomegalovirus

Principle  of  Tzanck Test

Giemsa stain is from the surname of a German chemist, Gustav Giemsa. It is also a type of Romanowsky stain. He prepared this Giemsa stain primarily for the detection of malarial parasites in blood smears, but now it is using in various sectors like histopathology and clinical microbiology, and more. It is a differential stain and consists of both acidic dye (azure and eosin ) and basic dye (methylene blue). This Giemsa stain is specific for the phosphate groups of DNA and attaches itself to where there are high amounts of adenine-thymine bonding. These two acidic dyes variably stain the basic components of the cells like the cytoplasm, granules, etc. Basic dye stains the acidic components, especially the nucleus of the cell, and therefore nuclei of multinucleated cells take blue color.

 Procedure of Tzanck Test

1. Unroof vesicle and scrape base with a scalpel blade
2. Smear onto a clean glass slide
3. Fix with gentle heat or air dry
4. Fix with Methanol
5. Stain with Giemsa
6. Make a working Giemsa stain diluting it 10 times with distilled water.
7. Cove the smear with this stain and leave for 20 -30 minutes.
8. Finally, wash the smear.
9. Leave for air drying and observe under the microscope.
10. Focus at 10X objective and finally observe at oil immersion lens (100X objective).                                                                                                                                                     

Result Interpretation of Tzanck  Test

Presence of multinucleate giant cells: Tzanck smear-positive

Absence of multinucleate giant cells: Tzanck smear-negative

Note: Tzanck smear: Positive

Tzanck test is positive as shown below-

Bibliography

1. Fields Virology Vol I & II, Editor in Chief: David M. Knipe & Peter M. Howley,  Asso editors: Diane E. Griffin, Robert A. Lamb, Malcolm A. Martin, Bernard Roizman & Stephen E. straus, 5th ed 2007, Publisher Lippincott Williams & Wilkins, Wolters Kluwer Health, USA.
2. Bailey & Scott’s Diagnostic Microbiology. Editors: Bettey A. Forbes, Daniel F. Sahm & Alice S. Weissfeld, 12th ed 2007, Publisher Elsevier.
3. Mackie and Mc Cartney Practical Medical Microbiology. Editors: J.G. Colle, A.G. Fraser, B.P. Marmion, A. Simmous, 4th ed, Publisher Churchill Living Stone, New York, Melborne, Sans Franscisco 1996.
4. Topley & Wilsons Principle of Virology  Editors: M.T. Parker & L.H. Collier, 8th ed 1990, Publisher Edward Arnold publication, London.