Sending pathology blocks and slides abroad: what to know
A written pathology report, the microscope slides, and the paraffin block itself are three different things — and which one (or which combination) you need depends entirely on what question the second opinion is actually trying to answer.
| What matters | Written report only | Slides | Paraffin block |
|---|---|---|---|
| What it lets a second pathologist do | Review the first pathologist's written interpretation — but not the tissue itself. | Directly examine the tissue's morphology under their own microscope, not just read someone else's conclusion. | Everything slides allow, plus cut new sections to run additional stains or molecular tests that weren't done originally. |
| When it's enough on its own | When the question is about the treatment plan built from an already-trusted diagnosis, not the diagnosis itself. | When the diagnosis or a specific marker needs independent confirmation. | When a marker is missing, borderline, or a newer test (that wasn't available or ordered at diagnosis) could change the plan. |
| What's needed to request it | A signed records-release request to the hospital's medical-records department. | A signed release to the pathology department specifically — a separate department from general medical records. | The same pathology-department release; some labs require a written justification for releasing the block, since it's part of the permanent medical record. |
Yes — re-review without a new biopsy is usually possible
If a receptor or biomarker result is missing, borderline, or in question, the original slides or the paraffin block can typically be sent for re-review or additional testing — in most cases without needing a new biopsy. That’s the whole point of keeping physical pathology materials rather than treating the written report as the complete record.
How labs release materials
Pathology departments generally require a signed release request — separate from a general medical-records request — identifying exactly what’s being asked for (report, specific slides, or the block) and where it should go. Processes and turnaround vary by institution, so the department itself is the only reliable source for exact requirements and timing.
Questions to ask the pathology department
- What exactly can be released — report, slides, block, or some combination?
- What's the expected turnaround once a signed release is received?
- Is there a fee, and does the department handle courier arrangements or leave that to us?
- Is the block returnable afterward, or is it retained permanently once released?
Courier basics and getting materials back
Paraffin blocks and prepared slides are stable at room temperature, unlike frozen specimens — standard courier services handle this routinely. Always request tracking and a delivery confirmation. Because slides and blocks are part of your permanent medical record, many institutions expect (or legally require) that borrowed originals eventually be returned — ask about the return process before you send anything, not after.