What Does “Pending” or “Additional Testing Required” Mean in my Pathology Report?

by Jason Wasserman MD PhD FRCPC
April 13, 2026

You have received a pathology report — or been told that your results are ready — but instead of a clear diagnosis, your report contains a note saying that results are pending, that additional testing is required, or that the case has been sent for further evaluation. This can be frustrating and unsettling, especially when you are waiting for answers about a serious diagnosis.

A pending result does not mean something has gone wrong. In pathology, an initial examination often raises questions that can only be answered with specialized tests, and those tests take time to complete. This article explains why pathology results are sometimes issued as pending or incomplete, what types of additional testing are most commonly ordered, and what you can expect while you wait.

Why is my pathology report pending?

When tissue or cells from your body arrive in the pathology laboratory, the pathologist begins by examining the sample under the microscope using a routine stain called hematoxylin and eosin (H&E). This initial examination can diagnose many conditions directly. However, in some cases, the H&E examination raises questions that cannot be resolved by looking at the cells alone, and answering those questions requires additional tests that are ordered after the initial examination is complete.

A report is typically issued as pending or with a note that additional testing is required when one or more of the following situations apply:

• The diagnosis is uncertain and requires confirmation. Some conditions look similar under the microscope. The pathologist may be able to narrow the diagnosis to two or three possibilities, but needs additional tests to determine which one is correct.
• The type of cancer needs to be identified more precisely — Knowing that cancer is present is sometimes not enough to plan treatment. Additional tests are needed to determine the exact subtype, which can significantly affect which therapies are recommended.
• Biomarker or molecular testing has been ordered — Many cancers now require testing for specific proteins, gene mutations, or other molecular features that guide treatment decisions. These tests are ordered as part of the standard workup but are performed after the initial diagnosis is confirmed, and add days to the turnaround time.
• The specimen has been sent for external consultation — Complex or rare diagnoses are sometimes sent to a specialist pathologist at another institution for a second opinion before the report is finalized. This is a routine part of quality assurance, not a sign that something is wrong.
• The sample quality requires additional processing — Occasionally a tissue sample needs to be processed differently — for example, cut at a different level or prepared differently — before a confident assessment can be made.

What types of additional tests are commonly ordered?

The tests ordered depend entirely on the clinical question the pathologist is trying to answer. The most common types are:

• Immunohistochemistry (IHC) — This is the most frequently ordered additional test in pathology. IHC uses antibodies to detect specific proteins inside or on the surface of cells. Different types of cancer cells produce different proteins, so IHC allows the pathologist to identify a tumor’s origin, confirm its type, and, in some cases, assess how likely it is to respond to treatment. IHC results are typically available within one to three business days after the initial H&E examination.
• Special stains — These are dyes applied to the tissue slide to highlight specific structures or substances — such as bacteria, fungi, mucin, collagen, or calcium — that are not clearly visible on routine staining. Special stains are used to diagnose infections, confirm certain tumor types, and evaluate conditions affecting the liver, kidney, and other organs. They typically add one to two days to the turnaround time.
• Molecular and genomic testing — These tests look for specific genetic changes in the tumor’s DNA or RNA — such as mutations, gene fusions, or amplifications — that are important for diagnosis or treatment planning. They include techniques such as fluorescence in situ hybridization (FISH), polymerase chain reaction (PCR), and next-generation sequencing (NGS). Molecular tests generally take longer than IHC, often one to two weeks, and in some cases, the tissue sample must be sent to a specialized external laboratory. These tests are a standard part of the workup for many cancers and are described in more detail in our Biomarkers and Molecular Testing section.
• Additional levels or deeper sections — A tissue block can be cut into many thin slices. Sometimes the pathologist needs to examine the tissue at a deeper level — cutting further into the block — to see a structure that was not visible in the initial sections. This is common with small biopsies, where the area of interest may not be present on the first few slides prepared.
• Consultation with a specialist pathologist — for example, a neuropathologist for brain tumors, a hematopathologist for blood cancers, or a dermatopathologist for unusual skin lesions. The slides may be reviewed in-house by a colleague or sent to an external expert. A consultation adds time but ensures the diagnosis is as accurate as possible.

How long will I have to wait?

Turnaround time depends on which additional tests have been ordered:

• Immunohistochemistry and special stains typically add one to three business days beyond the initial examination.
• FISH testing typically takes three to five business days.
• PCR-based molecular tests typically take three to seven business days.
• Next-generation sequencing (NGS) often takes one to three weeks, particularly when sent to an external laboratory.
• External consultation typically adds 3 to 7 business days, depending on the institution and the complexity of the case.

These are general estimates, and actual turnaround times vary by laboratory and institution. If the wait is causing you significant anxiety, it is entirely reasonable to contact your doctor’s office and ask for an update on when the final report is expected.

Will my diagnosis change when the additional results come back?

In most cases, additional testing confirms and refines the initial impression rather than overturning it. If the pathologist has already identified cancer on the H&E examination, the additional tests are most often used to characterize it more precisely, not to determine whether it is cancer at all.

That said, there are situations where additional testing does change the interpretation. An initial impression of cancer may be revised to a benign condition, or vice versa, once IHC or molecular results are available. In rare cases, a finding that appeared straightforward may turn out to be more complex. This is why pathologists order these tests — to ensure the final diagnosis is as accurate as possible before your care team makes treatment decisions.

When the additional results are available, the pathologist will issue either an updated report or an addendum — a formal addition to the original report that records the new findings. Your doctor will then review the completed report and discuss the results with you.

What should I do while I wait?

Waiting for a pending result is genuinely difficult, particularly when a serious diagnosis is possible. A few things that may help:

• Ask your doctor what is being tested and why. Understanding specifically what additional test has been ordered — and what question it is trying to answer — can make the wait feel less uncertain. Your doctor or their office should be able to tell you what test is pending and give you a realistic estimate of when results are expected.
• Ask whether any preliminary planning can begin. In some cases, enough information is already available from the initial report to begin certain steps — such as specialist referrals or imaging — while the final results are pending. Your doctor can advise whether this applies to your situation.
• Avoid interpreting partial results on your own. A pending or preliminary report is, by definition, incomplete. Trying to conclude an unfinished report — particularly one that uses technical language without context — is likely to cause unnecessary worry. The final report, reviewed with your doctor, is the right basis for understanding your diagnosis.

Questions to ask your doctor

• What specific test or tests are still pending, and why have they been ordered?
• What question is the additional testing trying to answer?
• When is the additional result expected, and who will contact me when it arrives?
• Has the initial examination already identified cancer, or is that still uncertain?
• Is the additional testing being done in your laboratory, or is it being sent to a specialized external facility?
• Has the case been sent for a second opinion from a specialist pathologist?
• Could the additional results significantly change the diagnosis, or are they expected to confirm and refine what is already known?
• Can any next steps in my care — such as imaging, specialist referrals, or planning — begin while the additional results are pending?
• When the final result is available, will I receive an updated report or an addendum to the original?
• If the result is still uncertain after the additional tests, what happens next?