Waiting for Pathology Results: Understanding the Lab Process

The most common assumption during this wait is that somebody already knows and is choosing when to tell you. Almost always, nobody knows. Your tissue is moving through a physical process that takes the time it takes, and the length of the wait carries very little information about the answer.

Tissue removed from your body goes immediately into formalin, which fixes it and stops it degrading. Fixation alone takes hours, often overnight, and longer for larger specimens. The tissue is then processed through an automated machine that removes water and replaces it with molten paraffin wax, embedded into a block, and cooled.

The block is sliced on a microtome into sections a few microns thick — thinner than a human hair — floated onto glass slides, and stained, most commonly with hematoxylin and eosin, which colors nuclei blue and cytoplasm pink and makes the architecture visible. Only then does a pathologist look down a microscope.

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

You may know that during some operations a frozen section is used: tissue snap-frozen, cut on a cryostat, stained, and read in roughly fifteen to twenty minutes. If that is possible, why wait days?

Because frozen sections are a compromise. Ice crystals distort the tissue and 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 — and not good enough to make a definitive diagnosis, grade a tumor, or separate entities 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 extend a turnaround, and most of them signal care rather than catastrophe.

Additional levels: the pathologist cuts deeper into the block to see more of the lesion. Special stains and immunohistochemistry: antibody-based tests that identify specific proteins and are used to pin down tumor type and origin. These commonly add several days and are the single most frequent reason a result is not back when expected.

Decalcification: bone and calcified tissue must be softened before it can be sectioned, which takes days on its own.

Internal or external consultation: pathologists routinely show difficult or rare cases to a colleague or a subspecialist elsewhere. The American Cancer Society notes 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 straightforwardly bad result is often diagnosable quickly.

Ask, at the time of the biopsy, roughly when results are expected, who will contact you, and by what route. Ask what to do if you have not heard by that date, then call on that date rather than waiting indefinitely, because reports do occasionally sit unactioned in a system.

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, and you can 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, and any second opinion later will need one.

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