Pappenheim Stain: Description of a hematological standard stain - history, chemistry, procedure, artifacts and problem solutions

Exactly 100 years ago, Artur Pappenheim published the final version of his staining procedure for blood smears ("panoptische Universalfarbung fur Bluttrockenpraparate"), in which he combined the Jenner stain and the May-Grunwald stain with the Giemsa stain. Since then, this stain has been referred to as Pappenheim stain or May-Grunwald-Giemsa stain. It provides a strong and reliable staining of the details of nuclei and cytoplasms, with prominent depiction of their granules. Pappenheim's stain is used worldwide with various modifications, which lead to inconsistencies in staining results that are not compatible with modern quality standards. There are no reports on quality assurance of hematological stains in the literature. Therefore, the task force Laboratorium of the German Society of Hematology and Oncology publishes this "Standard Procedure for the Pappenheim-Stain". This standard stain reliably produces inter-laboratory identical results in all cytological specimens of body fluids as well as tissue. The staining results parallel those published by Pappenheim in words and images. This standard procedure describes pre-analytical aspects, the staining in jars, and has associated quality assurance issues. Using a similar protocol, automated smear preparation and staining machines produce an identical staining result. We did not investigate staining on racks. We report on preliminary colorimetric data of correct and incorrect Pappenheim stains and describe correct staining using visual and colorimetric terms.