An official website of the United States government
Test Order
Pathologic or Molecular Evaluation of Fixed Tissues for Possible Infectious Etiologies CDC-10365
Omission of information on the CDC 50.34 Specimen Submission Form will lead to a delay in accessioning and testing, and potential rejection of specimen submission. Please include the following:
• Test order code
• Test order name
• Patient full name
• Patient birth date
• Date of death (if applicable)
• Specimen collected date
• State public health laboratory (PHL) institution name
• Patient ID (e.g., medical record number or autopsy number)
• Specimen ID (e.g., surgical pathology accession number)
• Original submitter contact information
• Comments (bottom of page 2): If unstained slides are submitted, the date that unstained slides were created should be provided here.
One electronically completed copy of CDC 50.34 Specimen Submission Form per case is acceptable ONLY when specimens are collected on the same day AND have the same surgical biopsy or autopsy number. Additional CDC 50.34 Specimen Submission Forms are required for specimens collected on different days or that have different surgical biopsy numbers (e.g., were from a different surgical procedure on the same day) or autopsy numbers.
Submission of an unredacted copy of: (a) the autopsy report (preliminary or final), or (b) surgical pathology report is required.
Requested additional information:
• A cover letter or copies of recent pertinent clinical notes outlining a brief clinical history, including relevant demographic/epidemiologic information
• Copies of pertinent laboratory results (microbiology, hematology, serology, culture, and/or biochemical)
• Relevant clinical, gross pathology, or microscopic pathology images, as available
• If paraffin-embedded tissue blocks or unstained slides are submitted, a block key listing the tissues in each paraffin-embedded tissue block.
Biopsy tissues and autopsy tissues from any organ or site are acceptable; however, tissue specimens should be submitted from the site(s) of the patient’s disease process.
If an infectious etiology is suspected, tissues should demonstrate histopathologic evidence of a possible infectious process.
1. Formalin-fixed paraffin-embedded tissue (FFPE) tissue blocks:
Preferred specimen type for histopathology, histochemistry (special stains), immunohistochemistry, PCR and sequencing, or nucleic acid extraction for transfer to other CDC laboratories. FFPE tissue blocks must be less than 10 years of age.
• Biopsy tissue specimens and autopsy tissue specimens (excluding brain): Only acceptable if embedded within 2 weeks after being placed in formalin.
• Brain autopsy tissue specimens: Acceptable if embedded within 4 weeks of being placed in formalin.
• For autopsy tissue specimens only, specimens in formalin for greater than 2 weeks (greater than 4 weeks for brain tissue) prior to embedding may be acceptable on a case-by-case basis.
2. Formalin-fixed wet tissues:
• Only acceptable for autopsy tissue specimens. Acceptable for histopathology, histochemistry (special stains), immunohistochemistry, PCR and sequencing, or nucleic acid extraction for transfer to other CDC laboratories, and electron microscopy.
- Autopsy tissue specimens (excluding brain): Acceptable if the duration of formalin-fixation has been within 2 weeks, or if tissues have been transferred to 70% ethanol within 2 weeks after initial placement in formalin.
- Brain autopsy tissue specimens: Acceptable if the duration of formalin-fixation has been within 4 weeks, or if tissues have been transferred to 70% ethanol within 4 weeks of initial placement in formalin.
- For autopsy tissue specimens only, specimens in formalin greater than 2 weeks (greater than 4 weeks for brain tissue) may be acceptable on a case-by-case basis.
• Biopsy tissue specimens: NOT acceptable for testing
3. Unstained paraffinized tissue slides:
• Acceptable for histopathology, histochemistry (special stains), immunohistochemistry. Only acceptable if created within 10 days prior to submission of specimens to CDC from an FFPE tissue block that was embedded within 2 weeks of being placed in formalin (or 4 weeks for brain autopsy tissue specimens). For autopsy tissues only, unstained slides from FFPE tissue blocks in formalin greater than 2 weeks (greater than 4 weeks for brain tissue) prior to embedding may be acceptable on a case-by-case basis.
• NOT acceptable for PCR testing and sequencing or nucleic extraction for transfer to other CDC laboratories
4. Formalin-fixed paraffin-embedded (FFPE) tissue scrolls:
NOT acceptable for testing
For more information, reference the Additional Information field.
•Process within 2 weeks of formalin-fixation of tissues
•Store at room temperature (15-25°C)
Autopsy specific, formalin-fixed wet tissue:
• The volume of 10% neutral buffered formalin used to fix tissues should be 10 times the volume of tissue
• Place thinly-sliced tissue in 10% neutral buffered formalin for 7 days.
• For brain tissue, place thinly-sliced tissue in 10% neutral buffered formalin for 2 weeks or longer until fully fixed.
After fixation, if not paraffin-embedded, tissues should be transferred to 70% ethanol for long-term storage and stored at room temperature (15-25°C). Unstained paraffinized tissue slides should be stored at room temperature (15-25°C).
Research or surveillance specimens may be labeled according to protocol. Labels should not include personally identifiable information. The results reported should NOT be used for diagnosis, treatment, assessment of health or management of the individual patient.
Paraffin-embedded tissue blocks should be shipped refrigerated with frozen cold packs during hot summer months to prevent them from melting.
Formalin-fixed wet tissue that is currently in formalin or has been transferred to 70% ethanol:
• Should be shipped in leak proof containers at room temperature.
• The maximum volume of formalin per primary specimen container cannot exceed 30 mL (excess formalin should be discarded prior to shipping).
• The maximum net volume of formalin per shipping package cannot exceed 1 L.
• If the specimen is in 70% ethanol, discard most of the ethanol prior to shipping.
• Leakproof containers should be placed in double Ziploc style bags and add sufficient absorbent material to the outer bag to absorb any potential leaks. Ship for overnight delivery.
Ship To:
[Insert CDC Point of Contact]
Centers for Disease Control and Prevention
RDSB/STATT Unit 109
1600 Clifton Road, NE
Atlanta, GA 30329
[Insert CDC Point of Contact’s Telephone Number]
All samples must be shipped in accordance with all applicable local, state and federal regulations. Upon shipment, submitter should send an email to the CDC POC providing shipping company, shipped date and package tracking number.
Paraffin-embedded cell blocks from body fluids (e.g., pleural, pericardial fluid) and aspirates (e.g., bone marrow) may be acceptable in select circumstances but assay sensitivity may be reduced; immunohistochemical, PCR and sequencing assays have been optimized for performance on FFPE tissue samples.
Freezing of formalin-fixed wet tissue can result in distorted histopathology and freezing artifacts (formation of interstitial and intracytoplasmic vacuoles resulting from ice-crystal formation). Specimens should not be frozen; specimens should be kept at room temperature (15-25°C).
CDC Pre-Approval Needed:
• Contact Infectious Diseases Pathology Branch Mailbox and pre-approval POC
Acceptable Sample/ Specimen Type for Testing:
• More specific guidelines regarding syndrome and pathogen specific tissue sampling and submission can be found on the IDPB website: http://www.cdc.gov/ncezid/dhcpp/idpb/specimen-submission/index.html
• Samples that are damaged or depleted are not acceptable for testing and will be rejected; this includes broken unstained slides, and FFPE tissue blocks that have been depleted due to removal of tissue sections from the block.
• In the setting of potentially scant paraffin-embedded tissue block samples, submission of original stained slides (e.g., H&E, Gram) may be requested.
• For small biopsies (such as liver), to maintain specimen integrity, we recommend existing FFPE tissue blocks be submitted as is, and not split, which might further reduce available tissue in the block.
• Scant specimens are subject to depletion during the course of testing.
• For autopsy tissues demonstrating decomposition, consultation with POC is required to determine acceptable specimen type(s) on a case-by-case basis.
•Autopsy tissue specimens in formalin greater than 2 weeks (greater than 4 weeks for brain tissue), may be acceptable on a case-by-case basis. Consultation with POC prior to specimen submission is required for this determination.
Turnaround Time is case-dependent:
• Human surgical biopsy cases it is 6-8 weeks
• Complex cases, routine human autopsy cases, and animal cases it is 12 weeks.
The course of testing will be determined by the clinical history, the histopathology observed, and the availability of specimens.
Content Credential