Practitioners frequently submit tissue and fluid samples to pathologists—typically employed at academic institutions, state laboratories, or private diagnostic laboratories—to assist them in the diagnosis of infectious diseases, inflammatory or metabolic disorders, and neoplasia in veterinary patients. Pathologists typically provide reports that include a description and interpretation of their findings, the degree of confidence in the diagnosis, a list of differential diagnoses, and recommendations for additional tests or procedures. The common goal for the practitioner and pathologist is to arrive at a correct diagnosis or to help narrow the list of differential diagnoses.

Sample submission complications that can result in an unsatisfactory outcome for practitioners include delay in obtaining a diagnosis, receiving an incorrect diagnosis, or receiving an inconclusive report. Many of these complications can be prevented if samples are submitted correctly and the practitioner and pathologist communicate well.

In this article, we answer common questions associated with pathology sample submission for cytologic and histologic examination and address a few of the problems that arise in the collection, submission, and interpretation of samples. The goal is to improve communication between practitioners and pathologists at all diagnostic laboratories and improve outcomes for optimal patient care.

Obtaining a thorough history is important in clinical medicine, and that applies to pathology as well. Unfortunately, it is relatively common for samples to be submitted with little, if any, patient history. Without a thorough history, practitioners may receive pathology reports that seem noncommittal or indicate uncertainty in the diagnosis. Pathologists may be reluctant to commit or express a high degree of confidence in a diagnosis if the cytologic or histologic findings are not straightforward and a thorough history is not provided. Treatment protocols and even the decision to euthanize a patient may be based on pathology reports. Thus, in the absence of key information about the case, pathologists may often provide a conservative interpretation.

At a minimum, patient signalment and any significant abnormalities identified from the results of physical examination, blood work, or diagnostic imaging should be provided. Furthermore, providing a working diagnosis or differential diagnoses list is often helpful to the pathologist in making an interpretation or ruling in or ruling out specific diseases. This information is crucial for successful communication between practitioners and pathologists.