XYLENE FREE DEWAXING
Mel John del BarrioAotea Pathology
Dewaxing
A.k.a “ Deparaffinization
A key point in the histology staining protocols
Dewaxing agents be miscible with alcohol, wax and SAFE!!!
Xylene
A mixture of three aromatic hydrocarbons isomers related to benzene
102 synonyms Alkylation of crude oil,
Dehydrocyclodimerization 1st used in the 1950s as a safer
alternative Safety was questioned in the late 70s
What Xylene Does?
Melts latex gloves Melts the soles of your shoes!!! CNS depression Skin, eye irritant Nephrotoxic/Hepatoxic Teratogen/Fetotoxic Bone Marrow suppressant Carcinogen?
Information about the health effects of xylene led laboratory supplier to come up with a safer substitute that would still do the job of xylene.
Xylene substitutes is widely available.
Various journals published the use of other chemical for dewax
Dishwashing soap
Is a detergent used to assist in dishwashing
Cheap As!!!
Readily available
How does DWS clean your dishes
DWS contains a mixture of surfactants
Sodium Lauryl Sulfate
Surfactants lower surface tension of water
Surfactants molecules are composed of hydrophobic and water soluble component
Sodium Lauryl Sulfate
Dishwashing soap in Histology
Used for cleaning Laboratory Utensils, Benches etc
Used to remove LCS (Ventana) from IHC slides
Dewaxing of Slides for Staining
Dewaxing with Soap
1st published in Laboratory Investigation journal in 2001
Sweden and USA A popular topic in Histonet
H & E (Modified)
Place slides in oven for 5 to 10 minutes @ 60 C
Place slides in waterbath heated at 70C for 1 min and repeat
Wash slides in running hot tap water
Stain Slides
Appendix, Breast, Bowel, Liver and Skin were used
Slides were placed in Ordinary slides and Superfrost Plus
Modified H&E protocol done Slides were randomly labelled Slides were evaluated by 3 pathologists Slides were rated from 1=Very Poor to
5=Excellent
Appendix
Bowel
Breast
Liver
Skin
Findings
All slides (normal and soapy) were rated between 3 to 5
Soapy slides where less superior
Diagnosis is not affected
Difficulty of distinguishing
Specimen
KW RM JM Average
Appendix5 3 5 4.33
Appendix (S) 4 3 5 4.00
Bowel5 4 5 4.67
Bowel(S)4 3 4 3.67
Breast4 5 5 4.67
Breast (S) 5 3 5 4.33
Liver5 4 5 4.67
Liver(S)4 3 5 4.00
Skin5 5 5 5.00
Skin(S)4 4 4 4.00
Conclusion
Dewaxing with DWS is cheaper to use
The health hazards of DWS is lesser
H & E staining times will be shorter
THANK YOU!!!
Acknowledgements
Dr. Karen Wood Dr. John Maccaferty Dr. Rupa Maitra Kerry Patience Abed Kader Rene Buesa Leanne Ward Kim Brown Emily Workman
Reference Buesa RJ, Peshkov MV. Histology without xylene. Ann Diagn Pathol. 2009
Aug;13(4):246-56 Lars Falkeholm, Crawford A. Grant, Anders Magnusson, and Eva Möller.Xylene-Free
Method for Histological Preparation: AMulticentre Evaluation. LABORATORY INVESTIGATION. Vol. 81, No. 9, p. 1213, 2001
www.histonet.com http://www.osha.gov/SLTC/healthguidelines/xylene/recognition.html http://www.oehha.ca.gov/water/phg/pdf/xylen_c.pdf www.wikipedia.co.nz Ventana IHC staining manual http://chemistry.about.com/od/howthingswork/f/detergentfaq.htm www.chemistry.co.nz
