Levels, Serial Sections and Deepers

Levels

• If one level is required (default): cut 100% into the “full face” of the block and take the next section
• If two levels are required: take the first section at full face and the second at the required level from the first.  For example, if 50 µm is required between levels of the A1 block, cut and discard 10 sections (5 µm x 10 = 50) and then take the next section for the second level.  When labelling slides, use  “A1-1 and A1-2″ as the block/slide numbers.
• Repeat this step for any further levels requested.  Ensure there is documentation of the distance requested between each level.

Serial Sections

Cut into the specimen until the first indication that tissue is visible. Cut ribbons and float on the waterbath until you have the required number of sections, making sure to note the order from first section off of the block to the last. It may be helpful to anchor the edge of the first section to the edge of the waterbath to maintain orientation of the ribbon.

Every section is saved (even the less than perfect ones), one right after another and placed on sequentially numbered slides (ex. A1-2, A1-2, A1-3, etc). Cut with even pressure and don’t interrupt cutting (after an interruption the first section will be thicker than the rest). Don’t throw any tissue away. This allows the Pathologist to see a cellular level by level of the biopsy.

Ensure there is documentation that the slides are serially sectioned.

Deepers

The Pathologist may request “deepers” after they review the initial slide(s). This block is returned to the same microtome where the block was initially cut (when possible) to ensure little loss of tissue. Of course, this is most important with tiny tissues.. Remember the tissue has already been cut to “full face” so the surface degree of cut may be dependent on the set up of the exact microtome. This is one reason it is ideal for histotechnologists to work at the same microtome so once they’ve initialed a slide there is no doubt which microtome the block was cut on.

However this is not always possible, especially in larger labs, so it is important to get used to using the fine adjustment knobs on the microtome so the best ‘next’ section can be taken for deeper levels.