Guideline and Booking
If you intend to use Immunohistochemistry Facility please contact Martina Tappe.
Further details can be taken from the operator and user regulations.
Recommended Tips for Sample Preparation
Sample collection and treatment prior to arrival at the IHC laboratory is of critical importance for the quality of histological or immunohistological staining.
Fixative:
- Neutral buffered formaldehyde (3.7-4 percent)
Formalin is the trade name for a saturated aqueous formaldehyde solution.
The concentration of a saturated formaldehyde solution is 40 percent (weight / volume) or 37 percent (weight / weight). This means that a 10 percent formalin solution contains 4 percent formaldehyde (weight / volume) or 3.7 percent formaldehyde (weight / weight).
- Methacarn
Methanol : Chloroform : Glacial acetic acid mix in a ratio of 6: 3: 1. Methacarn must always be prepared freshly.
Please use only glass containers for these samples.
Methacarn fixation is advantageous when immunohistochemical staining is planned because it does not come to a cross-linking of proteins and therefore no antigen retrieval is required.
Sample size:
Optimal are 3-5 mm thick pieces. Therefore bigger tissue samples should be cut into pieces before fixation. Hollow organs need to be sliced open.
Fixation duration:
24 - 48 hours
The penetration rate of formaldehyde is about 1 mm per hour. However, the crosslinking reaction is very slow.
The longer the tissues are fixed in formaldehyde, the more it comes to antigen crosslinking.
This could be disadvantageous for subsequent immunohistochemistry experiments. Therefore, in general please do not fix for more than 48 hours.
Small biopsies may only be fixed for a few hours.
Proportion of tissue to fixative: at least 1:10, optimal 1:20
Formalin is consumed during the fixation process; if too small amounts of formalin are left it could cause inadequate fixation. The containers in which the samples are fixed should be adapted to the size of the tissue.
The material should not be „squeezed“ into the container
The shape of the container should be cylindrical and the opening should be large enough to easily remove the specimen or plastic cassettes. The container must be tightly closed.
Appropriate containers can be purchased in the Immunohistochemistry Facility.
Labelling:
The cassettes must be labelled clearly legible with as few characters as possible.
Please use a pencil (Bleistift) for labelling as other pens will be washed out by alcohol or xylene.
Important:
In order to ensure the best sample processing, it is important that the samples are announced for dehydration as early as possible.
Samples that are to be dehydrated must be submitted to the laboratory not later than 2 pm Monday to Thursday***
The sample containers must be clearly labelled and contain the following information:
- Name:
- Department:
- Telephone number: