Problems and Solutions in Histological Technique

Prepared by

ROY ELLIS

IMVS Division of Pathology

The Queen Elizabeth Hospital

Woodville Road, Woodville, South Australia 5011

Sections adhere to the block on the upstroke of the microtome

One reason for this is static electricity, more commonly caused when the air is dry. Air in buildings where the air conditioning units are reverse cycle commonly have dry air. The humidity in the air is filtered out by the air conditioning units leaving the air very dry. Static electricity is not usually a problem in the tropics where the air is humid or in buildings which use evaporative cooling to air condition. This type of cooling raises the humidity which tends to remove static. Static of course is caused by friction between the block and the knife when cutting a section.
A knife clearance angle too fine causes the block to rub against the knife back usually causing deposition of wax on the back of the knife which in turn causes sections to stick to the knife.
If the knife is blunt then sections will compress and compressed sections tend to stick together and bunch up on the knife edge. So both of the above, can and probably will, produce adhere.
Dirty knife edge or a dirty underside of the block (residual wax) which of course cause sections to stick to the knife.

Click the button to return to the Home Page