Waiting for Pathology Results: Understanding the Lab Process

During this wait, most people assume somebody already knows and is choosing when to tell them. Almost always, nobody knows. Your tissue is moving through a physical process, and that process takes the time it takes. The length of the wait tells you very little about the answer.

Tissue removed from your body goes straight into formalin. That fixes it and stops it breaking down. Fixing alone takes hours, often overnight, and longer for larger samples. A machine then removes the water from the tissue and replaces it with hot liquid paraffin wax. The tissue is set into a block and cooled.

The block is sliced on a microtome into sections a few microns thick. That is thinner than a human hair. The slices are floated onto glass slides and stained. The usual stain is hematoxylin and eosin, which colors nuclei blue and cytoplasm pink and makes the structure visible. Only then does a pathologist look down a microscope.

The National Cancer Institute notes that preparing these fixed sections normally takes several days. A report usually reaches your doctor within about ten days of the biopsy or surgery.

You may know that some operations use a frozen section. Tissue is frozen fast, cut on a cryostat, stained, and read in roughly fifteen to twenty minutes. So if that is possible, why wait days?

Because frozen sections are a compromise. Ice crystals distort the tissue. The sections are thicker and less clear. They are good enough to answer an urgent surgical question. Is this margin involved? Is this node positive? They are not good enough to make a firm diagnosis, to grade a tumor, or to tell apart things that look alike. The slow route exists because it gives, in NCI's phrase, the maximum detail of the structures in a tissue sample.

Several things stretch out the turnaround. Most of them are signs of care, not catastrophe.

Additional levels. The pathologist cuts deeper into the block to see more of the lesion.

Special stains and immunohistochemistry. These are antibody-based tests that show which proteins a cell is making. They help pin down the tumor type and where it started. They commonly add several days, and they are the single most common reason a result is not back when expected.

Decalcification. Bone and calcified tissue must be softened before anyone can slice it, and that takes days on its own.

Consultation, inside the department or outside it. Pathologists routinely show difficult or rare cases to a colleague, or to a subspecialist elsewhere. The American Cancer Society says plainly that this may make the wait a few days longer.

Molecular testing sent out to a central laboratory, which can take two to three weeks.

Read that list again if you are counting days. Extra stains, a second read, and deeper levels are what a careful pathologist does when a case deserves more than a glance. They are not a sign that the news is worse than expected. A clearly bad result is often diagnosed quickly.

At the time of the biopsy, ask roughly when results are expected. Ask who will contact you, and how. Ask what to do if you have not heard by that date. Then call on that date, rather than waiting on and on, because reports do occasionally sit in a system with nobody acting on them.

Be aware that in the United States your report may appear in your patient portal before anyone speaks to you. You can decide in advance whether you want to read it there. You can also turn notifications off if you would rather not.

If you want a copy of the full report, you are entitled to it, and it is worth having. Pathology reports are the foundation of every treatment decision that follows. Any second opinion later will need one.

• American Cancer Society — Waiting for Your Biopsy or Cytology Test Results
• Cancer.Net — Reading a Pathology Report