This article provides observations on the features of sponsor-contract research organization communication that will achieve the best quality pathology report based on our collective experience. Information on the test article and any anticipated findings should be provided, and initial slide examination should be done with knowledge of treatment group (but may be followed by blinded review of target tissues to determine no-effect levels). Only a pathologist should write or revise the pathology report or the pathology section of the overall study report. To address concerns related to undue sponsor influence, comments by sponsors should be presented as suggestions rather than directives. Adversity should be defined for each finding by the study pathologist, but the no-observed adverse effect level should not be discussed in the pathology report. Board-certified pathologists are recommended, but are not essential. Sponsors that have a particular format or report preferences should make them known well in advance. Histologic processing "to glass" of protocol-specified tissues from all dosage groups is recommended for rapid evaluation of target tissues. Telepathology is beneficial in certain situations, but it is usually more efficient for the study pathologist and reviewing pathologist to be in the same physical location to review differences of opinion and reach a consensus.

AbstractNoncellular blood compartment (plasma or serum) and urine biochemical components are important indicators of overall animal health and can be used in conjunction with other parameters to investigate the toxicity of drugs and chemicals. This chapter describes the measurement and interpretation of clinical chemistry tests employed in toxicology studies in commonly used laboratory species. The introductory sections delineate methods for sample collection and data generation, and provide a general approach for data interpretation and reporting, with emphasis on distinguishing pre‐analytical/analytical variations from test material‐related changes. The following sections are organized by organ system, describing core clinical chemistry tests used in routine toxicology studies. These include protein, lipid and carbohydrate metabolisms, liver and kidney functions and electrolyte balance. Nonroutine tests evaluating cardiac and skeletal muscle, bone, blood vessels, the endocrine system, the nervous system are also presented. Because few clinical chemistry parameters are specific indicators of single organ toxicity, each section emphasizes the integrated interpretation of biochemistry changes with other study endpoints such as clinical signs, food consumption and bodyweight, haematology, electrocardiography, blood pressure and histopathology. Patterns of change are presented in the context of identifying organ toxicity.