Introduction

Anatomic pathology (AP) is the branch of medicine that examines tissue samples and cells by microscopy and other methods. AP seeks to answer clinical questions (e.g. Is it neoplastic? Is it malignant? Where does it arise? How can it be treated?) by rendering a diagnosis that allows the patient’s caregiver to treat the patient’s condition, predict the condition’s response to treatment and make a judgement about the condition’s prognosis.

AP comprises three activities: examination of tissue obtained from the body by biopsy, surgery or autopsy; examining exfoliated or aspirated single cells, circulating tumour cells, or groups of cells whose architectural context is often lost; and examination of deceased persons, usually to confirm or document a cause of death, or the extent of known or previously undiagnosed conditions.

Ancillary techniques such as immunohistochemical stains, (fluorescence) in-situ hybridization studies, molecular testing and advanced genomic and proteomic studies (e.g. next-generation sequencing, mass spectrometry) have complemented or even been incorporated into AP. The arrival of image analysis tools, machine learning algorithms and artificial intelligence systems will introduce new examinations to AP laboratories with a new set of risks and opportunities (e.g. automated quality control).

AP is different from other laboratory medicine specialties such as chemistry, microbiology, or haematology in several aspects. First, samples submitted for evaluation are often solid and, in many instances, unique (i.e. if the sample is exhausted or lost, it cannot be replaced by another sample) and indivisible (i.e. a part taken from the primary sample cannot be expected to have the same properties as the primary sample). Second, the structural integrity at the macroscopic scale determines diagnostic features such as margins status or orientation. Third, the examination process almost always requires at least two separate activities, macroscopic and microscopic examination, that occur at different times. Fourth, processing the sample involves many, often unrepeatable, manual steps, that introduce several risk points along the process. Finally, the analytical examination process is interpretive, performed by humans with intra- and inter-observer variability, and with no universally accepted biological reference intervals.

ISO 15189 , can be applied to, and encompasses AP. This document provides guidance for AP laboratories on how the requirements contained in ISO 15189 can be met. Like ISO 15189, this document applies to both the resource and process aspects as well as the governance and management aspects of AP. ISO 15189 defines medical laboratory as an entity performing examinations of materials derived from the human body for the purpose of providing information for a diagnosis.

In AP, examination is not synonymous with diagnosis. An examination has the objective of determining the value or characteristics of a property. The result of an examination in AP can influence, and even be the sole determinant, of a diagnosis. In many instances, however, a diagnosis rests not only on the result of the AP examination but also the clinical setting and results of other examinations (e.g. medical laboratory, imaging). Rendering a diagnosis constitutes practice of medicine. While this document must not infringe on the practice of medicine, it reminds users that the practice of AP is inseparable from the activities and requirements addressed by ISO 15189 and strives to promote the welfare of patients.

This document does not impose new or more stringent requirements than ISO 15189. Instead, this document attempts to clarify the requirements by providing examples of process actions and risks, using language and concepts familiar to the AP laboratory. The left column in each table refers to the subclauses in ISO 15189 for which guidance is offered. Not every subclause of ISO 15189 is addressed, only the subclauses for which clarification or guidance was thought to be of benefit. The tables in this document are not comprehensive lists of actions and risks. They are examples of actions and risks, and conformance with every item in these tables does not imply conformance with ISO 15189.

This document is aligned with ISO 15189 and assumes basic familiarity with central themes of ISO 15189, including process and risk management, corrective action for nonconforming work, internal auditing, and effective management reviews.

PD ISO/TS 23824:2024

Medical laboratories. Guidance on application of ISO 15189 in anatomic pathology

Current

Published:

31 May 2024