A nondiagnostic result means the pathologist could not make a diagnosis from the sample that was sent. Reports may also call it insufficient for diagnosis, inadequate, or unsatisfactory for evaluation. The result does not mean that something bad was found, and it does not mean that everything is normal. It means the sample could not answer the question it was taken to answer.
This article explains what a nondiagnostic or insufficient sample means and the words reports use to describe it. It also explains why it happens, how it differs from a negative result, and what usually happens next.
A nondiagnostic result means the sample did not contain enough suitable tissue or cells for the pathologist to reach a conclusion. Every biopsy, needle sample, or Pap test is taken to answer a question, such as whether a lump is cancer. When the material is too scant, damaged, or unrepresentative to answer that question, the pathologist reports it as nondiagnostic.
A pathologist will not guess at a diagnosis, because a diagnosis based on an unsupportive sample could lead to the wrong treatment or false reassurance. Reporting the sample as nondiagnostic is the accurate answer when the material is not enough.
Nondiagnostic results are common in some sample types and rare in others. They are seen more often with small needle samples, such as a fine needle aspiration, than with tissue removed during surgery.
Reports describe a nondiagnostic or insufficient sample in several ways, and the exact wording depends on the sample type and the laboratory. A few examples of how these lines appear in real reports:
THYROID, RIGHT LOBE, FINE NEEDLE ASPIRATION:
– NONDIAGNOSTIC. CYST FLUID ONLY.
LUNG, RIGHT UPPER LOBE, CT-GUIDED CORE BIOPSY:
– INSUFFICIENT FOR DIAGNOSIS. BLOOD AND FIBRIN ONLY; NO LESIONAL TISSUE IDENTIFIED.
CERVIX, PAP TEST:
– UNSATISFACTORY FOR EVALUATION DUE TO OBSCURING BLOOD.
These phrases fall along a range, from samples that could not be assessed at all to samples that could be assessed with some limits:
The difference between “unsatisfactory” and “satisfactory but limited” matters. An unsatisfactory sample does not answer, while a limited sample gives an answer that your doctor may want to confirm.
Looking up a word in your report?
Our Pathology Dictionary explains individual terms you may see beside a nondiagnostic result, such as “hypocellular,” “cautery artifact,” and “limited for interpretation.”
A sample is nondiagnostic for one of a small number of reasons, and the report often says which one applies. Most of these reasons are not anyone’s fault, and they reflect how hard it can be to sample a small or hidden area of the body.
Some of these reasons point toward a solution. A sample that missed the target may need repeating, while a sample made only of necrosis may need a different approach that reaches living tissue.
A nondiagnostic result is not the same as a negative result. The two can look similar on a report because neither one names a disease, but they mean very different things.
For this reason, a nondiagnostic result usually needs follow-up, even when nothing abnormal was seen. If you are unsure what your result means, ask your doctor whether the sample was adequate. Our section-by-section guide to the pathology report explains how to find the final diagnosis.
Cytology samples, which contain loose cells rather than tissue pieces, use standard reporting systems that include a category for nondiagnostic samples. Each system defines what an adequate sample must contain for that organ. Our article on the cytology report explains how these reports are organized.
Our thyroid nodule and NILM Pap test articles explain the other results these tests can give.
Sometimes a biopsy result is technically adequate but does not explain what the scan showed. The sample may contain only normal tissue, even though the imaging suggested a mass. Pathologists and radiologists compare the two results to check whether they fit together.
When they do not fit, the result is treated much like a nondiagnostic one. The needle may have sampled tissue beside the abnormal area rather than the area itself. Our article on pathology reports and imaging reports explains how this comparison works and what happens when the results disagree.
Before calling a sample nondiagnostic, the pathologist often tries to get more from the material already in the laboratory, so a new procedure is not always needed.
These steps help when some useful material is present. When the sample contains no suitable cells, no amount of extra work on the same sample can produce a diagnosis.
The next step after a nondiagnostic result depends on what was being investigated and how concerned your care team is. Options include repeating the test, using a different method, or monitoring the area over time, and your doctor will explain what applies to you.
When an HPV test is done at the same time as an unsatisfactory Pap test, a negative HPV result is not considered reliable, so both tests are repeated. If the repeat Pap test is again unsatisfactory, the 2019 ASCCP guidelines recommend colposcopy.
Reading the report from a specific procedure?
Our Procedures section explains the full pathology report from common procedures. Guides include the breast biopsy and bone marrow biopsy reports, and each walks through every result the report can contain.