Author: Kelsey Goldman, HTL (ASCP)

Last Update: 24 July 2023

Copyright: 2023,

Cite this Page! -> Goldman, Kelsey. “Bielschowsky.” HistologyOutlines.Com, 24 July 2023. Accessed (today) 

Special Stain

  • A silver stain to identify neurofibrils. Often used in Alzheimer’s Disease research (Litchfield and Nagy)
Control Tissues: Staining Pattern: Troubleshooting:
  • Do NOT use metal forceps, metal rods, or other metallic items in silver staining procedures. Plastic and glass are considered acceptable alternatives. Metallic items will react with silver solutions. The interaction will create black precipitate on the metal that could be seen on the slide and effect the staining quality. (Bielschowsky Silver Staining – Staining Protocol – LabCE.Com, Laboratory Continuing Education)
  • There is evidence that the staining process may be sensitive to changes in the temperature of the silver solution. Due to this evidence it is suggested that the histology lab have a policy in place that either indicates a required temperature of the silver solution or a maximum time that the silver solution is out of the refrigerator. (Litchfield and Nagy)
Biochemistry Theory:
  • Beilschowsky staining consists of a series of linear steps that each chemically alter the tissue to yield a visible product. In the first step the tissue is sensitized in a silver nitrate solution. The act of sensitizing places down silver molecules that have an affinity for the neurofibrillary tangles. After a wash to remove the silver nitrate, the slides are impregnated in a working ammoniacal silver solution. The working ammoniacal silver can be reduced with formalin in the next step. This reduction makes the silver visible. Sodium Thiosulfate removes any unreduced silver from the slide; yielding a cleanly stained product (Bielschowsky Silver Staining – Chemistry – LabCE.Com, Laboratory Continuing Education)
  • The overall mechanism of action in the Bielschowsky stain is not well understood (Uchihara)
  • Bielschowsky staining is an example of Argentophilic Staining in whitch the tissue itself can not reduce the silver; this requiring an extra chemical reduction step (in this case formalin) (Uchihara)
  • Amyloid and Neuritic components of the Senile plaque are stained along with the neurofibrillary tangles (Litchfield and Nagy)
Additional References:
  • Bielschowsky Silver Staining – Chemistry – LabCE.Com, Laboratory Continuing Education. Accessed 23 July 2023.
  • Bielschowsky Silver Staining – Staining Protocol – LabCE.Com, Laboratory Continuing Education. Accessed 24 July 2023.
  • “BIELSCHOWSKY TECHNIQUE – SENILE PLAQUES.” WebPath.Med.Utah.Edu, Accessed 24 July 2023.
  • Intorcia, Anthony J., et al. A Modification of the Bielschowsky Silver Stain for Alzheimer Neuritic Plaques: Suppression of Artifactual Staining by Pretreatment with Oxidizing Agents. preprint, Neuroscience, 6 Mar. 2019,
  • Litchfield, S., and Z. Nagy. “New Temperature Modification Makes the Bielschowsky Silver Stain Reproducible.” Acta Neuropathologica, vol. 101, no. 1, Jan. 2001, pp. 17–21, Uchihara, Toshiki. “Silver Diagnosis in Neuropathology: Principles, Practice and Revised Interpretation.” Acta Neuropathologica, vol. 113, no. 5, May 2007, pp. 483–99,
Sample Protocol:
    – Deparaffinize and hydrate to water
    – Immerse in 20% Silver Nitrate solution for 15 minutes in a water bath that had been preheated to 60C. Loosely watch the solution to make sure the water bath does not spike in temperature.

    – Wash in three changes of Distilled Water. This step must be done one slide at a time to achieve a proper wash.

    -Place slides into Working Ammoniacal Silver solution for 5-30 minutes. Make this solution right before staining and do not reuse it.

    Place directly into formalin solution for up to 5 minutes. Check the control under the microscope to verify the staining of Nerve Fibers turning black. Remove the slide from formalin solution once complete.

    -Wash in ammonia water

    -Wash in three changes of distilled water

    – Place slides into 5% Sodium Thiosulfate for 2 minutes

    – Rinse well in running tap water

    Dehydrate, Clear though Xylene, and coverslip
-Adapted from Bielschowsky Silver Staining – Chemistry – LabCE.Com, Laboratory Continuing Education. Accessed 23 July 2023.