Specimen Submission Guidelines for Pathologic Evaluation of Sudden Unexplained Infant Death with Pathologic or Clinical Suspicion of Infection
Sudden unexplained infant deaths (SUID) are defined as the death of an infant less than one year old, in which the investigation, autopsy, medical history review, and appropriate laboratory testing fail to identify a specific cause of death. Some of these cases have gross or histopathologic features suggestive of an infectious process and may be submitted for evaluation by the Infectious Diseases Pathology Branch. Performance of specific immunohistochemical, molecular, or other assays will be determined using clinical and epidemiologic information provided by the submitter and the histopathologic features identified in the submitted tissue specimens.
Collection of Tissue Specimens
Tissues should be collected in accordance with the National Association of Medical Examiners (NAME) protocol for a complete SUID autopsy. In cases where there is gross or microscopic evidence of an infection present, or when clinical history raises the suspicion of infection, tissue from the organ(s) demonstrating pathology should be sampled heavily and submitted for evaluation. Major organs without apparent histopathologic changes may be submitted representatively.
The NAME SUID white paper can be accessed online.
Submission of Specimens
Paraffin-embedded tissue blocks
In general, this is the preferred specimen and is especially important to submit in cases where tissues have been in formalin for a significant time. Prolonged fixation (>2 weeks) may interfere with some immunohistochemical and molecular diagnostic assays.
If available, we highly recommend that unprocessed tissues in 10% neutral buffered formalin be submitted in addition to paraffin blocks.
Although not optimal, if paraffin blocks are unavailable it may be possible to utilize unstained sections cut at 3–5 microns (10 slides per block) for immunohistochemistry and special stains but not molecular diagnostic assays (e.g. PCR).
Send separately on dry ice.
Electron Microscopy (EM) specimens
Samples fixed in glutaraldehyde and held in phosphate buffer. Sample containers are filled to the top with phosphate buffer and sent on wet ice. Do not freeze. Epoxy-embedded tissues are also accepted.