Collecting and Fixing Tissues

Histopathology Tissue Submission Collecting and Fixing Tissues

Collecting and Fixing Tissues

Tissue collection
Collect tissues using sharp scissors or scalpel blades and mouse-tooth forceps. Handle tissues gently. Grasp and cut samples at the edges, so the areas of interest aren't damaged. At right is a section of mouse spleen damaged by rough handling. Many of the cells are distorted beyond recognition.

There are many fixatives and many considerations in their use.  For routine paraffin processing and most stains, neutral buffered 10% formalin is a good choice. In general, mouse tissues should be fixed in formalin for 24 to 48 hours, but can be left much longer. Our standard fixative for rodent tissues is 75% ethanol-10% formalin. The ethanol speeds fixation and stiffens tissues such as lung for easier trimming. Bouin's is good for mouse embryos and fetuses, but is not as forgiving, and the tissues must be adequately rinsed after fixing to remove the picric acid. Fixatives can be purchased from vendors of scientific supplies. Contact us if you're not sure what fixation protocol to use.

Use plenty of fixative!

In general, the ratio of fixative to tissue (vol:vol) should be 15:1 to 20:1. Dense (skin, bone) and bloody (liver, spleen) tissues are hardest to fix. If the amount of fixative is inadequate, or the sample is too large or too thick, the interior of the specimens won't be properly fixed. Inadequate fixation is one of the most common problems we encounter.

Fresh tissues tend to stick together and to the bottom of the container, which inhibits fixation. Thus, it's a good habit to swirl the containers a time or two to separate the tissues from each other and from the container bottom. If there is a lot of blood in the fixative after tissue collection, replace it with fresh fixative.

Tissues must be placed in fixative promptly to prevent autolysis. Refrigerating the fixative and specimen containers slows autolysis. Sometimes additional procedures are needed. For example, lungs might need to be infused with fixative to approximate the normal state of inflation, and intestines may need to be injected with fixative or opened for optimal fixation. At right is a section of mouse large intestine in which the mucosal morphology is lost due to autolysis.

Additional News and Announcements

  • UAB Institutional Signing Official Change Effective November 9, 2015

    Effective Monday, November 9, 2015, please use the following name and title on all OSP submissions for external sponsors requiring the name of the UAB Institutional Signing Official:
    Richard B. Marchase, Ph.D.
    Vice President for Research and Economic Development
     The remaining contact information, address, email and phone numbers, should remain the same:
    AB 1170
    1720 2nd Avenue South
    Birmingham, AL   35294-0111
    Phone:  205.934.5266
    Fax:  205-975-5977

    Any submissions in progress, in route or received by the OSP, will be updated to reflect the correct signing official.

    If you have any questions please contact the OSP at

    Posted by Office of Sponsored Programs | 11/05/15
  • Research Infrastracture Update

    IRAP - the Integrated Research Administration Portal - is an electronic tool that uses interconnected software modules to enhance each phase of the research process at UAB, from alerting investigators to new funding opportunities with the SPIN and SMARTS modules, to facilitating transfer agreements on research materials. Many documents can be shared across modules, eliminating the need to fill out redundant forms. Significantly, IRAP’s battery of more than 130 reports gives investigators granular data on the status of their submissions, so they always know where they are in the process. IRAP also allows administrators to improve workflows and procedures by finding and fixing bottlenecks in the system. In turn, this helps Research Administration offices work to deliver a better customer experience and to focus on improving customer service overall.
    Posted by Office of the Vice President for Research and Economic Development | 10/30/15
  • Notice of Proposed Rulemaking for the Federal Policy for Protection of Human Subjects

    ​A Notice of Proposed Rulemaking (NPRM) has been published seeking comments on proposed changes to the Federal Policy for the Protection of Human Subjects. The UAB Office of the IRB (OIRB) is requesting input from the UAB research community on the proposed changes in order to respond most effectively to the NPRM. The proposed rule includes significant changes to the regulations governing human subjects research. Among these changes are more relaxed requirements for certain categories of lower risk research and more stringent requirements for informed consent, especially in regard to use of biospecimens.
    Posted by Office of the Institutional Review Board for Human Use | 10/30/15
  • IRB Continuing Training Requirement for 2015

    ​UAB IRB policy requires continuing training once in every three year period for key personnel involved in human subjects research.  The UAB Office of the IRB has worked with the CITI Program to create different continuing training courses for (1) Biomedical and (2) Social/Behavioral/Educational researchers.  UAB personnel may complete either of these courses to meet continuing training requirements.  Both courses require investigators to complete three required modules and three of six elective modules. 
    Key personnel who completed their initial human subjects training before January 1, 2015 are required to complete one of the continuing training courses prior to December 31, 2015.  This continuing training will be valid for the 2015-2017 period.
    Additional information, including step by step instructions for registering, can be found on the OIRB website:  Continuing IRB Training.
    If you have questions about IRB training requirements, please contact the Office of the IRB at 934-3789.
    Posted by Office of the Institutional Review Board for Human Use | 10/09/15
  • New UAB Institutional Core Facility Program Launched

    The UAB Office of the Vice President for Research and Economic Development (OVPRED) announces the launch of the UAB Institutional Core Facility Program (ICFP), created to promote the development and operation of outstanding Core Facilities that can serve the needs of UAB investigators.
    Posted by Office of the Vice President for Research and Economic Development | 10/02/15
  • Change in State Law Regarding Age of Consent

    On May 7, 2015, Governor Bentley signed into law Act 2015-167, which lowered the age of consent to 18 years old (previously 19 years) for IRB-approved research conducted by an accredited college or university. This means that 18 year olds may now consent for themselves to participate in research conducted at UAB under IRB approval. The IRB has updated most of its forms with this information and will continue to revise policies and procedures to recognize this change in the law. The revised forms must be used for all submissions received in the OIRB after September 1, 2015.
    Posted by Office of the Institutional Review Board for Human Use | 06/26/15
  • IRB Form Changes - June 2015

    UAB IRB forms have been revised as of June, 2015. New versions of these forms will be required for all submissions received after September 1, 2015. These include: Human Subjects Protocol, Investigator's Progress Report, Sample Consent Form, Checklists for new submissions for both full and expedited reviews, Checklists for renewal submissions for both full and expedited reviews.
    Posted by Office of the Institutional Review Board for Human Use | 06/26/15
  • Confidential Disclosure Agreement Templates Updated

    UAB’s template confidential disclosure agreements have been updated and are available at the OSP Confidentiality Disclosure Agreement (CDA) webpage. The following confidential disclosure agreement (CDA) templates are available:

    Mutual Confidential Disclosure Agreement (Company and UAB disclosing confidential information);

    Unilateral Confidential Disclosure Agreement (Company Disclosing to UAB); and

    Unilateral Confidential Disclosure Agreement (UAB Disclosing to Company)

    Please use, and encourage the contracting party to use, the appropriate UAB template CDA. If the contracting party can agree to the terms of one of UAB’s template CDAs, UAB will sign the agreement without further routing and review, resulting in a more expeditious process.

    Please forward any questions regarding the CDA process, or UAB’s template CDAs to

    Posted by Office of Sponsored Programs | 06/22/15
  • Policy Update: Definition of a Principal Investigator

    Effective May 18, 2015 UAB’s Definition of a Principal Investigator policy is modified with regard to UAB employees in the 02 (Full-time Temporary) employment status or other UAB employment categories. See the full policy at the link or via the UAB Policies & Procedures Library.

    Case-by-case inquiries should be addressed to
    Posted by Office of Sponsored Programs | 06/01/15
  • Expired Form FDA 1572 continued use approved

    ​On April 30, 2015 the Form FDA 1572 on the FDA website at is expired.

    The FDA is in the process of updating and posting a new Form FDA 1572. Even though it is expired, the FDA approved continued use of the current form.

    We will monitor the FDA website and will post notice of the new form's release, when available.

    Posted by Office of the Institutional Review Board for Human Use | 05/06/15
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