When a serious diagnosis such as colorectal cancer is first made at a local clinic and you decide to be treated at a larger hospital, you often leave holding several pieces of 'test material' — stained slides, paraffin blocks, a pathology report, and a referral letter. The names sound unfamiliar, but once you understand what each one does, it becomes much clearer where they should go.
During a biopsy, the removed tissue is set into a wax called paraffin to form a 'block.' Very thin shavings of that block are mounted on glass and stained to make a 'slide.' A pathologist examines the slide under a microscope to decide whether it is cancer and what type it is. The block acts like an 'original master,' because if additional staining or genetic and biomarker (biomarker) testing is needed later, fresh slices can be cut from it. That is why the block is an especially precious item.
When you transfer your care, the key point is to bring these materials to the hospital that will actually treat you. Its pathology department usually re-reads the outside slides and block (a slide review) and, if needed, runs further tests from the block. Slides, blocks, reports, and imaging CDs are generally handed in at outpatient registration or the pathology desk on the day of your visit. If you want to know in advance, calling the hospital's call center or patient referral office to ask 'where do I bring the imaging CD and the outside pathology slides and block' can set your mind at ease.
It also helps to keep the materials from being scattered across several places. The same block cannot be submitted to two hospitals at once, so it is best to gather everything at the hospital that will make the final surgical and treatment decisions. If you stop at an interim hospital along the way, you can show only a copy of the report there for reference while keeping the original block to submit at the treating hospital. Some first-testing hospitals ask that 'the slides be returned after surgery,' because they are obliged to keep their own patient's pathology records for a set period. Checking in advance whether the material is borrowed or can be kept after submission helps avoid confusion later.
Finally, when you receive the materials, photograph the list and note how many slides and how many blocks you have, so nothing is lost in transit. The exact stage, whether it has spread, and whether surgery or chemotherapy comes first are often decided only after further imaging (such as CT) and a re-reading at the larger hospital, so try not to feel too anxious if every answer does not arrive at once right now.
This article is general information and does not replace individual medical care. How materials are submitted and the order of testing and treatment can differ by patient and by hospital, so please always discuss your situation with your own medical team.